I don't think they were really following his every whim nor would I call it a legion. I just think they were trying to stay out of his way and do their normal thing (eat humans). Remember that one bold SOB who tried to get to that one guy when the ape titan was trying to ask him about the 3D gear? He certainly wasn't trying to listen.
I'd say that it is HEAVILY implied that the people who created the walls and have been in charge did so for control. They are concerned with keeping the citizens in a fish bowl. They have stifled innovation, kept secrets, and I'm pretty sure that they allowed the scouting legion to exist ONLY to insight fear into the people and make them scared to want to leave the walls. While we don't know the specifics, I'd say it's save to assume that Rod and anyone else who runs things are not doing anything for the people.
That titan did stop for a second before continuing, maybe it is just a bad case of ADHD ^^ the others however did stand back and waited until the beast titan gave them the permission to eat Mike.
In all likelihood, control was one of the reasons why the Reiss family created the walls and kept the humans from wanting to go outside the wall and maybe you are right that the scouting legion was literally formed to be death fodders. And considering that the titans are outside these walls I think that is a good enough reason to not to go outside. It's a fight they just can't win. Sure the newest chapter confirmed there were other human civilizations outside the walls but we have no idea if any of them are still alive today.
Think of the Night of the Living Dead (or almost any other zombie movie for that matter). You and few others are stuck inside a house and zombies are everywhere outside. Do you seal the house completely so the zombies can't get in or break through the zombies to attain freedom? The latter one is considerably more risky and not often the better option despite the higher rewards and is usually only done when they can't stay hidden, but if you had infinite supplies you could even just try to live in the house and just stay there forever as taking on the zombies would be a futile endeavor considering how numerous they are.
And for me, this is what it basically boils down to. The titans are simply overpowering the human race and they can't fight them so they tried to seal themselves inside a fishbowl and stay safe that way. Killing people for daring to push the envelope is probably going to far and as I don't remember the peoples inventions particularly risking a war with the titans I am not gonna justify their executions. But I think the government's paranoia of the titans is more of a factor than their hunger for power as the titans would simply eradicate all of them completely. And lets face it, any character who thinks humanity has an optimal chance to beat the titans either lacks a clear understanding of the power difference or really desperate. Most members of the scouting legion are both as they all know there is an enormous power difference they cannot bridge and they still don't even know which titans are behind all of this or why.
tl;dr: I think hiding behind the wall was the most logical option because humanity simply can't combat the titans on a equal level. Sure the government is an ass but it's better than being titan food.