The majority of people did nothing to stop him and still, day after day, does nothing to stop him. The whole Republican party feels unthreatened enough by being voted out by "the majority of Americans" that they enable Trump.
Where are your second amendment guys? Still in full support of tyranny? The only guys trying to get a shot at your politicians are psychos and dumb idiots who want to become famous. Not a single hint of politics - except as a show - in their empty head.
Most Americans have families and shit and don't want to go to jail for doing something violent towards a politician. This is, broadly speaking, a good thing, we really don't want any random schmuck vigilante to constantly attack politicians that they don't like.
I'm not going to judge the majority of people for "not doing anything", because what you're suggesting would put them (and a lot of other people, some of which are innocent) at risk. I'm certainly not going to risk going to jail or facing capital punishment to hurt a politician, even if I thought it was a net good for the country.
I'm definitely not a "second amendment" guy though, I don't really think most people should have guns.