If you incite violence, by saying that we should set fire to hotels full of people, then that's a crime. If the people in the hotels are mostly not White British, then that's going to be taken as racism, particularly if the context was lots of rumours about a murder being carried out by an immigrant.

She could have disputed all of that, of course. But she pleaded guilty.

(Also, those are normal hotels, just currently being used to house asylum seekers.)