The racism part simply comes from them growing up at a time when they were the only race around. Everyone else is a newcomer, an interloper. And I'm not even sure it's really a 'race' thing so much as a culture thing. The newcomers don't just look different, but talk different, dress different, eat different and act different, after all. The homophobic thing comes from the religion.
I don't think, though, if you did a questionnaire for a thousand seniors and a thousand immigrants half their age you'd find the old people were more kookily religious, homophobic or racist than the newcomers.
Agree on everything you said.