It's like regularly using strict (incidentally, yet another default that has been changed in more recent versions of Perl).

Firstly, I agree with the move to safe defaults. I may even have had some influence on changing the only mind that matters in that regard with strict. I'm not certain of course, but the change did come shortly after that discussion.

I'd rather adapt the language defaults to the way its users actually think

I'm in favour of that also. But the crux of our disagreement is whether your assessment of how they think is correct. And I believe you are not.

As you've agreed that the vast majority of uses of regex are against single line strings, I find it strange that you don't see that when they describe /^foo/ as "foo at the start of the line" that they aren't simply assuming -- with good cause -- that the 'start of the line' and the 'start of the string' are the same thing. Analogously ditto for the other two. Because with single line strings, that is so.

The fact that their wordy description isn't factually correct when dealing with multi-line strings doesn't change the fact that it is a good assumption for the majority of uses.

And once they start dealing with multi-line strings -- if they ever do -- there are other things that must be taken into serious consideration in addition to those three. And in my uses of dealing with multi-line strings I've usually found that I need to make explicit provision for dealing with newlines. That is to say, I explicitly don't want '.'s to match through newlines; but rather want to use embedded newlines to restrict the scope of preceding wildcards.

I can see we'll not agree here, but I still think that it is better for people to apply both /s & /m on the basis of need rather than as a 'it comes as recommended' cargo cult.