The (UK) Labour party has had a lot of anti-semitism issues in the news recently, including an mural which included caricatures of two Jewish bankers, two separate council candidates posting holocaust denial content, and a former London mayor making repeated revisionist statements about Nazi Germany (though he doesn't deny that the holocaust happened).

Excuses include: For Corbyn, he hadn't seen the mural before opposing its erasure, Christine Shawcroft's is likewise that she didn't see the holocaust denial post before defending the person who made the post, for Alan Bull, he was only sharing it rather than endorsing it, and he's dyslexic, for Ken Livingstone that he was only stating historical facts, none yet for Roy Smart apart from a case of mistaken identity.

I can't recall hearing about things like this a decade or so ago. I don't know if this is because of an increase in incidents, or because such incidents are more likely to attract attention nowadays.

Has the level of scrutiny / opposition research, either by those within the Labour party, people in other political parties, those in the media, or those in social media, increased? Also, is it easier to do opposition research when it involves content on social media?

If attitudes towards anti-semitism have changed, why have they changed? While some, such as @LeaveEUOfficial, have blamed it on Labour wanting to get the Muslim vote, as far as I can tell, none of these politicians are Muslim, and at least some of these politicians don't have much of a Muslim constituency. Allan Bull's attempted ward of Stanground South has only 76 Muslims out of 8000, and Sugar's attempted ward of St James is only 2% Muslim - there's only three times more Muslims than Jedi Knights.