You realize that TES is essentially a god's dream right? That means anything can and does happen.
No.
Pronged Pickle: There is a principle. The law says we are guilty UNTIL proven innocent. How can we be truly guilty of a crime with no chance to prove our innocence? The law is clear but it only applies when actually accused of a crime punishable by prison time. being sent to the block magically has no until proven innocent shot.
Your word isn't accepted as evidence, especially on crimes such as treason against the Empire. Being sent to the block doesn't magically make it have no innocent shot, your character only had their word. Nothing else.
I acknowledge that what Ulfric Stormcloak did was against Imperial laws and the Legion have every right to capture him and his followers, and execute them all for high treason against the Empire. I'm not going to sit back and debate against it, however Ulfric does have a legit complaint that the Empire has proven to themselves to be too weak, and therefor in Ulfric's eyes, and the eyes of others who are his followers, the Empire is deem unfit to rule his homeland. He went from fighting for his Empire to now fighting against it. If the Empire was strong and was healthy then they would've pile drove the Dominion out of their country, and win the Great war without signing the WGC.
The Empire wasn't strong and healthy after the Great War. At the end of the war, they had lost three entire Legions and the rest were down to half strength. If the Empire had a full strong force of 18 Legions, they only had enough Legionnaires to fill 7.5 Legions. The Empire most likely didn't have the full 18 Legions, they could of possibly had only 10 Legions (The highest number mentioned in the Great War) that would mean they only had 3.5 full Legions at the end of the war. Not enough in either case to continue the war.
The White-Gold Concordat was needed, it was needed to rebuild and regain strength. The Empire got it's ass kicked in the Great War, but it also gave them the focus they needed. They're preparing for a large scale war, the final war.
Many Nords understood the need for peace, High King Istlod (whom Ulfric calls a true High King) also understood the need for peace when he accepted the White-Gold Concordat for Skyrim.
The Civil War is a distraction, it's merely an interlude for what is to happen between the Empire and Aldmeri Dominion. It is easy to call the Empire weak and unworthy, but Nords have never been fair weathered friends. If they're going to abandon the Empire at it's lowest point, then the thousands of Nords that died in the Great War sacrificed themselves for nothing.
The Empire was never going to win the Great War, Titus knew this, his Generals knew this. But the Empire met them on the field the battle, they weren't going to take plops cause of the mere threat of war. Even a weakened Empire managed to be victorious over a strong Aldmeri Dominion. You will often get people in here saying the Empire will abandon you the second Cyrodiil is threatened. That is untrue, the Empire fought in Hammerfell until all the Legions were recalled for the Battle of the Red Ring, in the final year of the war.
After the war, the Empire had to recover a lot. Now you may ask why it is taking so long, that is because like in the Civil War. Criminals, bandits, evil wizards etc. They took advantage, there were outbreaks of violence throughout Cyrodiil. Wayrest was lost in High Rock.
The White-Gold Concordat is in favor of the Aldmeri Dominion, why? Because the Empire went to them for peace. If someone came to you after you fought them in a war, asking for peace. Are you going to make peace in their favor, or yours?
The Empire may seem weak in Skyrim, Tullius isn't getting reinforcements. He just lost an entire garrison. Tullius is going to get reinforced, Pale Pass was closed and is being cleared by the Empire. The Legion has regained much strength, with enough personnel to assemble a new Imperial force to go into Skyrim after Pale Pass is cleared. They have enough personnel to escort trade shipments into their nation.
What the Woman officer did back in Helgan was not a best representation of the Legion, especially when it comes to new players like myself, at the time. If this kind of practice is quite common then the Legion is going to continue to lose support from their Imperial citizens. They're suppose to protect their imperial citizens, not to snatch them up and use the “oh they might be a potential threat” and therefor execute them. This causes an uproar against the citizen's as those who they execute have families and friends that becomes disgruntled. If you poke around in the beehive eventually you will get stung by a bunch of angry swarming bees.
The situation at Helgen is the Empire being desperate. Tullius believes the Thalmor are to blame for this uprising, that they stirred up trouble in Skyrim. To cause the Empire to waste resources and man power. The execution, wasn't the finest hour of the Empire. It was their desperate hour. They simply cannot take the chance, they need this rebellion crushed and order restored so they can get back to facing the real enemy.
While Tullius isn't the most friendliest or respectful man towards the Nords, he's also just as angry as Ulfric is. He's angry about this rebellion, but he's also angry about the Thalmor. He hates the Thalmor so much, he himself talks about almost wanting to join the Stormcloaks because of what the Thalmor make the Empire look like. Throwing their parties to make the Empire look bad, forcing Tullius to be there at times.
Everyone has families who are torn apart by this Civil War. How many Legionnaires have family, have friends. The Legion doesn't take pride in executions, it never has, but it is something that has to be done to send a clear message.
From a long time ago,
DrunkenMage pointed me out on Ufric's Thalmor's dossier that the Thalmor was trying to stop his execution from happening back in Helgan, which explained why the Thalmor Ambassador was there on her horse. Did Tullius get bought out by the Thalmor? Shouldn't Ulfric be executed first? Instead they executed 1 of his Stormcloak men, and then attempted to execute the player.
Tullius would never get bought by the Thalmor, he hates them with a passion. He talks about war with them, he even says he considered joining the Stormcloaks because he hates the Thalmor so much.
One of Ulfric's men rushed forward to the block, you were called next. It was most likely they were saving Ulfric till last. Sending a powerful message by him watching his men die, then him being killed and his head goes to Cyrodiil (I know you call it disrespectful, but it's to send a message not only to Skyrim, it sends a message to all in the Empire.)