I'm one of probably the larger JS fans, and even love working with NodeJS (don't shoot me please) -- but I totally agree with you. I would certainly not trust myself, I really wouldn't trust somebody else trying the same.

I don't see a huge problem using some JS blockchain library for some non-critical application if it somehow added to the end product, but something so highly critical... no thanks.

Except for the part about Tezos. I haven't looked into it.