There are two different sets of rules that your bitcoin node uses to validate new data it receives from other nodes. The most important rule set is called consensus. These rules are checked against new blocks that are sent across the network. If we fuck up consensus it creates a chain fork. Eventually one fork will win and the other will lose. The transactions that were confirmed on the losing fork will be reversed when the fork is eventually resolved. In this scenario the price of bitcoin will plummet, trust in the system will degrade, and every bitcoin business loses a ton of money.

The other set of rules is far less critical. It's called mempool policy, or policy for short. This ruleset is applied to new transactions that are received from the bitcoin peer-to-peer network and its purpose is to prevent DoS attacks on the whole network. Transactions that fit within this ruleset are called 'standard'. Non-standard transactions will simply be dropped by your bitcoin node. No chain fork, no problem really, except for the person trying to get this transaction mined. If you want to get a non-standard tx confirmed (like one with a giant script such as a large inscription) you need to skip the bitcoin peer-to-peer network and send it directly to a miner. Most inscriptions are standard and are sent through the bitcoin p2p network.

I have seen conflicting stories about whether Ocean is actually censoring these transactions. We will know for sure when they mine a block. According to the Ocean dashboard, median time to next block is 14 days, so in Two Weeks™. Regardless, I fully expect Luke DashJr to censor inscriptions given his public statements and his work on bitcoin core patches intended to accomplish exactly this goal.