I didn't realise they would be setting this up as a debate (since my points were actually more nuanced) but some sense of what I said. https://www.bbc.co.uk/news/uk-wales-66464173
Welsh language: Is mixing with English causing 'erosion'?

One campaign group has claimed bilingualism is "always a threat" for a minority language.

BBC News

@drswissmiss if Swedish didn't use words from other languages it would be a very different language. More cumbersome but still Swedish. Loan words don't lessen a language though!

I don't speak Welsh as the tuition for it in the early '90s was dreadful at my school and my family didn't speak it. This Welsh-only stuff means I'm essentially excluded from (one of) my own culture(s).

@Flamekebab yes, the second point is one of the reasons why I think that not worrying too much about purity is needed! More people will feel they can try and use it.
But I do understand the concerns that if there's too much English in it, in future people will just use English.
For first point - English is same - tons of French, Latin and other words! It's very different from Old English but English just the same.
@drswissmiss A fascinating debate! Certainly agree that language isn't fixed, it's so interesting!