With stamps the explicit goal was to bloat the UTXO set. Their marketing framed that as "unprunable".
Counterparty was designed before SegWit and due to fee spikes around that time was pretty much unmaintained afaik.
BRC-20 is just crazy. JK, I have no idea how that one works.
https://bitcoinexplainedpodcast.com/@nado/episodes/bitcoin-explained-76-stamps-and-the-invalid-block-caused-by-it