This is something that has haunted me from the start that I used minecraft forge mod loader. When the mod folder contains mods that are supported in a different version of minecraft, the game crashes and I need to delete them all. So that also means that I can't play forge on different clients if they are different versions. 

When there is a fabric mod installed, it is a different story. The game gives a message that the mods are not supported, and then it continues to work without them. I would like this to work in versions too. This will save a lot of time and frustration and also makes it clearer for people who doesn't know you have to get the right version for the right loader.

Use separate installs for separate versions/modpacks, it’s very simple to do using the official launcher and ensures you don’t have this issue or break your worlds

We have decided that it is a far better user experience to get real feedback if you install a mod incorrectly. In the cause of mods for wrong versions this is doubly important because if you share the same worlds directories, and load a world in the wrong version/mod set, then you could easily lose data from that world. What you're advocating for is explicitly to make it LESS clear to people who do not get the correct versions of mods, by almost silently ignoring them and pretending like everything is fine.

We find that the use of launcher profiles is not a overly complicated ask, and most people can figure it out fine. So that is our recommended approach.