I really wonder how legal that is. Or more precisely suspect it is very much illegal.

like think about it it's pretty much a tool which intentionally silently sabotages you if you try to compete with the tool maker

It is like selling a hammer but putting in the TOS that you must not use it to build a hammer factory and if you do the hammer silently will sabotage you...

Or image Microsoft would add a window kernel job which sometimes crashes Steam "to make it less efficient to use windows to "compete with the MS app store".