2012 is not relevant. The rules were updated in 2017, giving these vendors plenty of time to become compliant. Some did, and remain in the App Store. Those that refused to stop installing MDM profiles were blocked/removed.
Deal with it. Update your apps. Crying to the EU or complaining you used to get away with it but now you don’t is not going to change Apple’s mind about MDM use outside the enterprise.
You think Apple releasing Screen Time is relevant to them cracking down on vendors abusing functionality meant only for enterprise use, but it’s a bigger issue than just Screen Time type apps. The crackdown on the abuses of features and capabilities meant for enterprise but used in customer-facing apps has been ongoing, with even Google and Facebook getting busted recently.
Furthermore, Apple has nothing to gain financially from blocking those MDM-abusing apps, and in fact their revenue and profits suffer for having done so. I don’t understand the anticompetitive angle that’s being pushed. If Apple were selling a Screen Time app that argument would at least make sense, but that’s not the case here.
There are plenty of apps that compete with Apple, including email, notes, camera, file sync/backup, video and music rental/streaming/purchase, messaging, podcast, FaceTime, maps, keyboards, calculators. emoji/Animoji, alarms/timers, photo library and many more—including Screen Time type apps. One thing all those available apps have in common is that they do not violate rules and restrictions against non-enterprise use of MDM.
btw PR spin from companies with apps blocked due to MDM abuse may not be the best source of information.