This "most people", "most atheists" and "most Christians" gets thrown around a lot as well, quite often by the very same people complaining about over-generalization. You think about that for a second.

"Most" depends on where you draw the borders on this particular map. It's a statistical fact that "most" people in the USA are Christian, and even including those who aren't, somewhere around 40-45% do, in fact, believe that evolution didn't occur. Speaking literally, yes, "most" people accept evolution, but in context, highlighting the fact that up to 45 percent of people hold views contrary to reality due to nothing but religious beliefs isn't a mistake. Not in any way, shape or form.

You say you don't care what people believe, and that's just an outright lie. Of course you care. You care the very second they try to impose rules and limitations on you because you don't believe what they believe. Think gays, lesbians, atheists, Arabs (because "they" generally don't care if an Arab is actually a Muslim or not, "they" just assume it) or anyone that simply stands in their way. You might say it's fine that they're wasting money building a Creation park in Kentucky (or wherever, I don't really remember), but what if a large part of that money is your tax dollars? You might say it's fine that churches don't pay taxes, but what if they still expect further benefits from the state, as well as unquestioned influence over government elections?

We want people to be happy too, but we'd rather focus on those who are currently the victims of religion being happy, than those who can only find happiness in ensuring their religious faith over the well-being of others.

There are plenty of theists who are good people. That said, there are plenty of theists who are horrible people. The problem is that, whenever this is discussed, it's a very one-sided conversation where us atheists are the only ones actually pointing this out, while the "good" theists are busy making sure even the raging bigots have the right to state-sanctioned bigotry. I just don't accept that situation, and neither should you. Especially if, as you claim, you're really interested in people being happy.

TL;DR Don't tell me to not care about the people who most needs caring about, because you feel uncomfortable when people point out actual, observable reality.