Many people bought it expecting more, because the studio promised a lot more. You can say that's on the people for not checking before buying, but that doesn't invalidate the dishonesty on their part.

Were it an early access game, you would in fact be purchasing expecting updates. Not guaranteed updates, but certainly expecting them. This game was an amazing early access release in all but name.

I'm not saying you should word it as updates you paid for, you just don't word them as if they're an act of generosity. Just call them "updates", not "free updates" like you did right before the reply that put "free updates" in quotes.