are nearly 20% of English people really so fucking stupid & prejudiced that they blame Jews for any disaster ?
I doubt it, but I imagine if you presented such statements in Muslim countries you'd get far higher statements of agreement.
Lots of people are stupid and impressionable and assent to stupid fake shit without fact checking. This is universal and it applies as much to supporting Black Lives Matter (which wants to defund the UK police, smash capitalism, etc., which is fine if you agree with that, but most people don't), as it does to agreeing to idiotic conspiracy theories when presented with them
Essentially you could make up any ridiculous shit and people would say yes, because a substantial proportion of humanity is impressionable as fuck. And to the extent that this is influenced by existing prejudices then people will believe it.
For example, it was claimed that David Cameron had fucked a pig. This appears to be a completely made up statement that had originally been quoted by a comedian as 'if you accuse someone of fucking a pig then you force them to put out a 'I did not fuck a pig statement''. Anyway, people were extremely willing to believe that David Cameron had fucked a pig, because they wanted it to be true. Maybe it is. But people who liked Cameron would be less likely to believe it, and those who don't like him more likely.
This is confirmation bias, and sometimes it leads people to reject bad things which people genuinely did do, such as rape, because they don't want it to be true.
I don't think it's accurate AT ALL to say 20% of English people believe Jews created covid-19, because it was a push statement.
The valid polling technique would be to ask an open-ended question, not ask people to directly deny that Jews had anything to do with it.
Also when you present people with no less than 48 statements, all false, and you do it online, with a range of answers from 'do not agree', 'agree a little', 'moderately', 'a lot', 'completely', then you are going to get a lot of people avoiding answering everything with 'do not agree', simply because that's how people answer studies.
It doesn't mean that 20% of people believe this.
If you look at the study
www.cambridge.org/core/services/aop-cambridge-core/content/view/9D6401B1E58F146C738971C197407461/S0033291720001890a.pdf/coronavirus_conspiracy_beliefs_mistrust_and_compliance_with_government_guidelines_in_england.pdf
then of all the 48 ridiculous idiotic statements served up to people online, then the one about Jews came last. People were much more likely to believe that the US created covid-19 as a bioweapon.
People were more likely to believe that it was a conspiracy to make Brexit look better, that the coronavirus vaccine will contain tracking microchips, and all manner of other batshit insane things.
Stupid people ask stupid people stupid questions and get stupid answers.
Who knew.