A lot of small block proponents defend their stance by reasoning that an artificial cap is necessary to prevent spamming, and thus bloating the blockchain. How effective is Monero's mechanisms at making any kind of spammy bloat attack to costly or difficult to pull off.
Say for example, a malicious user had 200,000 XMR (approx 420,000 USD, or 1.5% of all XMR) and their sole intention was to bloat the blockchain to use as propaganda that small blocksize caps were necessary in the Bitcoin debate over the blocksize, the user in question is motivated to drive home the point by making poor Monero an example because they dare question static blocksizes. Given that miners can't discern where coins are coming from so will have difficulty filtering out the spam, how much damage could a user like that do? How long could they keep it up and how big would the bloat fallout be? Could someone bloat the blockchain hundreds of gigs in a couple of months for example?
I ask this because the flex blocksize is a huge selling point WRT scaling the Monero system in a decentralized manner, and I often wonder whether it is vulnerable to this kind of exploitation, and if it is, how much harm could they conceivably do? It was also pulled off in the past to a limited extent by another hacker trying to exploit a bug, but I'm not sure if they did much harm, if any.