The reality is, tribalism and convenient categorization is everywhere, and the United States is not immune. Just because there might be a legal system in place to address discrimination in its various forms does not mean you won't run into close-minded, hateful individuals as you walk down the street. As Bruce Hornsby sang years ago, "Because the law don't change another's mind When all it sees at the hiring time Is the line on the color bar"
Of course not. This is not black-or-white, all-or-nothing. There are shades in between.
When a country makes discrimination illegal, it forces people to stop doing it and slowly over time their minds will change, because otherwise they'll run afoul of the law. These days discriminating against a gay person in Canada is akin to discriminating against someone because they're female - it's unheard of, and you'd be quickly silenced and given a stern talking to, if not disciplined (if it was in the workplace)
If the US would hurry up and make discrimination of gay people illegal, the mind-set of people would slowly change. Maybe it would take a generation (or even two), but it's better to start that process now than x years from now.
The United States constantly labels itself the best country in the world, the pinnacle of democracy and freedom, etc. when unfortunately the reality for millions of people is not so good.