They're not illegal immigrants until their asylum applications are processed and their status determined.
The biggest problem in the UK is ignorance, not immigrants. If those protesting outside hotels are so concerned about people coming to this country and sponging off, they should be enraged about the likes of Amazon, Google, Twitter (X), and all the other massive corporations who get lots of corporate welfare (our tax money) but pay no tax.
Neoliberal capitalism has led to this and it will only get worse. Even if net migration was brought down to zero, "our own" homeless and poor will still be in exactly the same dire situation as they are now. The narrative around migration and refugees is causing mass hysteria and misdirected anger in the most ignorant and gullible, which the likes of Farage are exploiting