It's an ideological issue. Some people need someone they feel superior to to distract them from how the people who consider themselves to be better than them are abusing them, by saying that some other group is actually responsible for the problems they are actually causing.

Thus the rich, conservatives in charge who are cutting jobs and creating immense inflation by allowing anticompetitive behavior by large corporations they make money from, blame the losses on immigrants. And immigrants have no way to fight back as they have no rights.

Ideological issues are more difficult to use as a distraction these days. It's just harder to convince people that their inaction in failing to repress or murder people who are just trying to live their life will cause their deity or whatever to be disappointed or disown them and keep them out of paradise or whatever they believe. So, it's not as effective to just say they're evil, anymore, they need to invent things those people are doing to them even if they aren't doing anything in reality. Problem is it's becoming more and more apparent that trans people aren't actually a threat, so they need to invent things like statistics saying that 50% of major mass shootings are done by trans people by inventing criteria to make only 8 or 9 of the thousands of mass shootings to be considered "major", and thus the 4 mass shootings they found that were by trans people become 50%. As long as they keep repeating those numbers and isolating their audience from real statistics, it's easy to maintain control that way. But the internet makes that difficult these days. Plus the economic issues are much more common among conservatives than having trans children. And trans people aren't quite as historically repressed as POC who were slaves or immigrants who were running from horrible conditions, so its more difficult to keep them repressed. Same was true of gay, lesbian, and bi people a couple of decades ago. They were repressed, but not as economically repressed as POC and immigrants making them more likely to fight back and easier for conservatives to identify with.