Yes, and this is exactly why ATProto is worse and more dangerous. Instances are safer. precisely because they are more genuinely decentralized.
The ability to forever tie your stuff to a person, strongly, is exactly what the surveillance state would want.
Mastodon's model gives you plausible deniability. It's safer.
I'd say atproto gives you a clear sense of what's tied to each of your identities — you can go and explore your repo in a browser. There's nothing to say your identity has to be "tied to a person" anymore than your Mastodon account on some server is "tied to a person". It's true atproto has a "scraping is the default, so expect it" vibe, whereas maybe you're arguing Mastodon allows security by obscurity?
I don't think I agree. There's nothing intrinsic about the PLC and PDS servers that tie an AT account tighter to your own identity, than an account on an ActivityPub instance in my opinion.
Correct me if I'm wrong, but I'm guessing by plausible deniability you mean that ActivityPub essentially forces you to shred your old account if you need to move instances? Apart from the fact that AT also doesn't impose a "one DID per human identity rule" (yet?), allowing you to move between AT identities and PDS instances as much as you like, there's no hindrance to anyone that really wants to track your account movement between AP accounts of they even slightly want to do so. By default ActivityPub leaves a little entry on your old account saying "the person behind this account move to instance so-and-so", which is what allows you to migrate your followers with you in the first place, but that leaves just as much of a trail than your DID moving from PDS to PDS, and if you want that message to not be there, giving you said plausible deniability, you're just back to creating fresh accounts every time, just like AT.
I mean I think it's hard to say that one platform is better than the other in that regard because the platforms are really really similar to each other from a broad perspective. If you take ActivityPub, break up the concept of an instance into one part that keeps the data and one part that shows the data, scrap the usernames in favor of random IDs, and stick a few more services in between, you've already arrived at the AT protocol, the oversimplification aside.
Nothing is stopping you from making more identities, though?