I used to think Jeremy Corbyn was an anti-semite. I also used to think Roald Dahl was an anti-semite.
But after researching what they actually said, it's clear that they were just smeared, because they weren't racist enough against Palestinians and (shockingly) thought Palestinians deserve human rights.
Honestly, I am now highly skeptical whenever someone calls another person an anti-semite.
He said those things towards the end of his life after he had been smeared for years.
Prior to that interview in 1983, he had criticized Israel for the atrocities they committed in Lebanon and people called him an anti-semite for comparing Israel to Nazi-Germany.
Eventually, he said fuck it, and went full anti-semite.
I don't blame the guy. He's only human and people can only take so much shit before they turn into bitter old men.
I think the government or the Labour party updated their definition of what anti Semitic meant to include any criticism of the Israeli government a few years ago, which also says a lot.
I can't comment on either of them, but I agree with your last point and I will absolutely forever be suspicious of anyone labeling others as antisemitic.
It's like when white Americans brand a political movement or activist as racist. You know they're likely full of shit and you just need to do some very light reading before it all falls apart.