Choosing how and in what direction a character develops their skills is an essential component of DnD. Removing that ability would akin to removing controlling them in combat, and both contribute to understanding how those characters even work.
I don't have an issue per se with auto-leveling as an option (although it seems like a waste of dev resources to me). But not allowing you to make Gale a divination wizard instead of evocation or Laezel a Gith-friendly monk takes away from the experience for others.
Don't want to respec? Then don't do it, and everyone gets what they want.
