What distinguishes GNU licenses from more permissive licenses is that the GNU licenses require derived works be released under an appropriate GNU license as well.
This is not quite anti-commercial, but does put the kibosh on some otherwise viable business models. If you wish you could incorporate some of this code in a proprietary product that you can sell licenses to, then what's wrong with the GNU license - from that stand point - is that it forbids that.
That's the intended purpose of the GNU licenses - to promote software that respects user freedoms by making it easier to write such software (because of access to existing GPL/AGPL code) relative to the ease of writing software that infringes on those freedoms.
As a necessary side effect, it is also the case that you cannot move GNU-licensed code into a non-GNU-licensed-but-compatible codebase without changing the license to an appropriate GNU license. Code can move the other way, from compatible permissive license to GPL.
Sort of the worst case, in terms of unintended consequences, is code under an incompatible-but-otherwise-free license, where code can't move either way for not really any good reason.
Fortunately, people seem to have generally settled on GPL-compatible licenses, whether permissive or copyleft.
It is quite clear to me that the parent's intention was to challenge the ritualistic "Why not MIT/BSD?" type of argument. It is the author's prerogative to decide which license the software should be under. While I use permissive licenses for my work usually, I see the merit in GPL licenses and might even switch back to it at some point. They serve different goals, and I suspect that in future we're more likely to converge towards GPL-like licenses.
GPL protects the rights of independent developers better than permissive licenses; and as software development becomes more accessible, we're likely to see more work pocketed off by companies without giving due credit, or even entirely forked off. GPL clearly recognizes that companies will not give back unless required by the law. If we're to have a fairer and more decentralized (political) power distribution, we need the protections of the GPL.
If I could flick a switch to turn all OSS projects to GPL, it'll impact the entire industry in a good way. OTOH, changing everything to permissive licenses will have absolutely no impact.
It seems plenty possible, hence my explicit note that I was assuming otherwise. It doesn't seem clear - I've encountered people asking that question honestly and I tried to give an honest answer. To the degree that I'm a partisan in this discussion I am pro-GPL, but I think it's worth acknowledging the legitimate points raised by reasonable people on the other side.
The effective license will of course look very similar to the GNU license, since following the GNU license conditions will most of the time also mean that you are in compliance with the permissive licenses conditions, but there are exceptions. For example, GPLv3 do not forbid distributors to use the authors names in the promotion of products, but it is compatible (under the additional terms section) with 3-clause BSD that explicitly do forbid such promotion.
