"Mass deportations, now, set fire to all the fucking hotels full of the bastards for all I care, if that makes me a racist, so be it".
Racist maybe, although she doesn't seem to care about race.
Offensive, yeah, seems that it could be interpreted as offensive, but thats not technically illegal (the high court has repeatedly affirmed to right to be offensive).
Inciting violence (the offense she was convicted of) no, not at all, she was stating her political opinion and her belief that the lives of immigrants is worth less than british children.
Although people will point out she admitted guilt, but the threat of significant pre-trail imprisonment was used a lot at this time to force guilty pleas.