> I mean that to protect the proverbial technology-challenged grandma it should be the default.
Yes, I agree.
> And that it should even s,http://.*,,g them out.
No. Links are very useful and constantly present in conversation and manually written into messages. Do you seriously propose to basically ban them by default? Also I don't want the MUA to censor messages, that would also lead to a lot of confusion.
If anything, they could not render them as hyperlinks by default, but stripping them out, no.
Hot take: MUAs should simply not make links clickable/copyable on render, or even strip any URI away completely.