I think it’s in poor taste to force something like this. This doesn’t follow the open and inclusive views of which WP was founded.

Similar to recent rants about skeleton/starter themes needing to be “full featured” upon activation to be allowed in the repo, defeating the purpose of their existence. Some say this is what Github is for but I say why force one type of user out of the wealth of what the repo provides just because they are not the Theme Team’s preferred type of theme user, all the while these same people are theme authors themselves creating an obvious conflict of competitive interest.

Who cares, if it’s annoying or not uniform, uninstall the theme if the notice is unwanted, no one is forcing you to use said theme. Otherwise let theme developers provide whatever call-to-action they like upon activation/updates etc. The stifles creativity and there could be a wealth of utility removed by this forceful policy chosen by only only a few. As long as there are no nefarious intentions, leave it be. Does no one research a theme before installing it?