The thing that is patentable isn't "a vibration". It's the exact, specific means through which you produce that vibration.
We've gone from completely dumb eccentric rotating mass vibration to trackpads that you'd swear are actually physically clicking, or the Ice Cubes demo in in Nintendo's 1-2-Switch[0], both of which use linear resonant actuators. Those actuators are themselves a complex enough piece of technology to warrant a patent, and the techniques to simulate the feel or real physical objects using those actuators are pretty damn non-trivial as well.
As a general rule, I find that the patent system is problematic but, within the scope of the system as it exists today, these are perfectly reasonable things to patent.