Like words, animals, society, and everything else, symbols evolve. Some lose the meaning they once had, others are co-opted by groups of people who think that symbol represents them. I don’t exactly know how the rainbow became an LGBT symbol but it is and it is a fabulous one and it is, unfortunately, the only example of this I can think of off the top of my head that isn’t a hate group. The swastika was a symbol of good fortune, once upon a time and look what happened to that one. We can sit here and swap history lessons but, in the end, once a symbol has been co-opted by a hate group, all the good things that symbol might once have represented gets lost in the static of ugliness. If you want to get mad about that, get mad at the people who stole the symbol and made it ugly, not at the people for whom that symbol has become a calling card of violence.