The UK continuing to fund Eurovision is like a masochist paying their dominatrix. They keep giving us a good kicking and we keep coming back for more.
Suggest you read these to understand a bit more about the European Broadcasting Union - https://www.ebu.ch/home , https://en.wikipedia.org/wiki/European_Broadcasting_Union .
The Eurovision Song Contest is only part of what they do.
Though if the Tories dismantle the BBC, you'll get your wish, since EBU membership is for publicly-funded broadcasters only.