In fairness , JWs are by no means the worst offender in this regard. There are some real weird ( and even damaging ) "religions" claiming charitable status.
Interesting article here:
https://www.civilsociety.co.uk/news/the-commission-should-remove-the-advancement-of-religion-as-a-charitable-purpose-says-report.html
Among other things , it states that 12,000 UK charities list "advancement of religion" as their sole charitable aim.