How is ION immune to the attacks common to p2p networks?

[Nuhvi]

I exhausted Twitter's capacity for communication in good faith, so I am trying again here.

@csuwildcat points out the fact that p2p networks are vulnerable to many attacks that can render them unusable, which is definitely true. But I am struggling to learn how is Bitcoin helping ION do any better.

Here is my understanding of how ION nodes joins the network for the first time:
1- See a transaction on Bitcoin with ION marker, and a CID in the OP_RETURN
2- Discover peers announced on that CID from IPFS
3- Download the content of that CID from these peers, resulting in more CIDs pointing to the actual update operations.
4- Discover peers announced on these CIDs from IPFS (I guess this step can be skipped, assuming the previously discovered peers had all the rest of the data anyway).

My question is, doesn't that mean the system depends can only be as resistant to p2p attacks, as much as IPFS is?
If IPFS is indeed resilient in the face of spamming of topics / CIDs, then do you think IPNS is also just as good as ION at delivering routing (service endpoints) if key rotation is not a requirement?

Thanks for your time.