It is just a convenient way to convert the crypto to fiat that these processor handle for their customers. There are ways to handle this step without a third party (P2P exchanges are one).
Less convenient for sure, but ultimately if you care about your economical freedom you will adopt them... or you will live in a walled garden, at least as long as your activity fits the current agenda/policies of these intermediaries (and your government). As soon as you don't, you get kicked out/cut from the system, even if your activity is not illegal.
A closer comparison would be to a bank that doesn't let a you deposit the cash your business earned at the end of the week. It would be an annoyance, but it doesn't actually prevent you from conducting your business.
Except that, as we have seen, Bitcoin rarely is used for "we need financial freedom" activities and mostly for "buy into my Ponzi scheme" activities.
Someone could have constructed the crypto equivalent of PayPal. Someone still could and maybe right now is even better since the Ponzibros are getting hammered.
Unfortunately, nobody seems to be doing it. That speaks volumes.
Self-sovereignty and self-custody prevent third-parties from making decisions for you like this, and the removal of intermediaries (like payment processors) also prevent anyone from restricting you ability to transact with your desired counterparties.
The kind of freedom this enables also has disadvantages of course, but I strongly believe the few real "bad" transactions that gets blocked by the current system are a drop in the ocean compared to the billions of people deprived of access to the system and the millions of others who are included but seriously limited in what they are "allowed" to do on it.