I believe he does like his job. It is the activism being forced upon him by his employer that he does not like. Nor should he. No employee should be forced to promote something that they are fundamentally opposed to. It is not the place of an employer to force politics upon their employees, quite illegal.
My company is in the middle of a big diversity campaign right now. There's mild pressure to participate, the department gets points for participation with the area with the most diversity points getting a plaque or something, but it's not overbearing and it doesn't count against me if I don't. And all hyperbole aside, I doubt that it's much different at Home Depot. I doubt that this guy is forced to do much of anything except to live with the fact that his company has an "LGBT Month". And that bothers him. Well, if it bothers him that much then quit. Go to another big-box store that doesn't observe it and he should be happy.