Admittedly, I know very little about Kneecap. Never heard any of their music let alone follow their drama.
But what little I have heard about them, usually in the form of some type of outrage piece in the media has been pretty benign, such as their Glastonbury appearance. Critical of the state of Israel and their on-going genocide against the Palestinian people, yes, but in no way indicative of any kind of underlying anti-Semitic sentiment.
https://www.cbc.ca/news/politics/kneecap-ineligible-canada-1.7638108
Meanwhile we've got a MAGA guy who supported Jan6 touring coast-to-coast, sometimes on public land, spreading his version of 'love'.
Feel free to set me straight about this situation and the band, but off-hand this looks like Starmer's gaslighting of UK is spreading here.