I understand how irritating it is to be playing competently and have an antsy healer start yanking you around the battle area (I had the neural silencer enabled regularly in WoW), so I do support your suggestion to be able to disable Rescue in certain content. Nobody needs to be yanked out of their leylines by a healer who's having a bad day.

That being said, I feel that you're presenting the issue a little bit disingenuously. Two dungeons where a new tank may cause issues for a party of sprouts, and a well-placed Rescue can fix things up quite well, are Brayflox's Longstop and Dzemael Darkhold. In Brayflox's Longstop, I've had new tanks who are so focused on keeping themselves out of the venom on the final boss that they don't realise it's healing the boss. In Dzemael Darkhold, I've had tanks who won't move the eye into the crystal-affected area so that it can actually take damage.

New tanks will regularly not read the chat. Further, my data center contains Typhon, Kujata and Tonberry, and thus we have a large language barrier in parties. (I can and do give instructions and tips in both E and J, but most are not bilingual). All the good intentions and explanations in the world won't help a tank who isn't reading chat because they're tunnel-visioning, or who doesn't speak your language (auto-translate is often not robust enough). This is just something that happens with a lot of new tanks. It's to be expected, and it's totally okay. We have a tool to deal with it. Rescue is your best tool for a smooth and efficient resolution.