More likely it's enthusiasm and surplus energy finding an outlet.
Licensing is cited often. For coreutils? Whose lucrative commercial scheme has a custom tail(1) as its secret sauce? Doesn't make sense to me. Looking at the top contributors it's some Rust enthusiasts and a Debian project Director. I'd expect to see hardware manufacturer employees or similar if this were about licensing.
(hand wavy, non-detailed explanation - read other sources for clarity)
So the MIT license is less restricted for users, but ultimately only in the interest of people looking for profit, not consumers
Don’t take anyone’s word for what they say or which is better. Read them.
This seems like a pretty straightforward consumer benefit that anyone should be able to acknowledge regardless of which license they develop with.
I don’t recall if file(1) is part of coreutils or not, but there was a somewhat unexpected exploit for it a few years ago.
To be fair there are daemons and scripts that shell out to these things and when all the stars align you maybe get an exploitable scenario - but these tend to be situations where doing that in the first place was a bad idea (e.g. $PAGER is not meant to be a load bearing security component and rewriting in Rust is unlikely to fix all the issues with this class of usage).
Longer answer: It's hard to find programmers who can or are willing to write/maintain code in the style of the old GNU hackers. Starting afresh with modern development practices in Rust is more likely to result in a project that gets actually maintained over the long term after those old hackers die/retire/etc. Starting afresh also allows you to bring in more prosocial practices that are table stakes for modern OSS development but would be met with resistance from the GNU community, including using a permissive license and having and enforcing a Code of Conduct.