If a company does something bad, you can sue to fix it.
Suing sets legal precedent and forces all companies to abide by the ruling, more or less.
But now if a company tricks you out of your right to sue by putting arbitration clauses in everything, then you can’t sue. You can only have a (hopefully) impartial third part tell the company to stop doing something specifically to you. The company is still free to keep doing the thing to everyone else, and their arbitration doesn’t affect any other companies also doing bad things.
There are other issues too.
Like when McDonalds offered free fries or something for everyone who used the app, but then quietly changed the terms of service for the app to include forced arbitration.