the people who don't agree can keep running the old versions of the node :confused: this is how bitcoin vs bitcoin cash came to be, or ethereum vs ethereum classic
even though a monero classic also exists, it's waaay more unpopular than those other crypto's counterparts, it's like if it doesn't exist because it's not even traded anywhere, because everyone agreed to monero's upgrades and have been keeping up so far and there has been no point in keeping the old software version
like right now: the next upgrade being FCMP, people are free to keep using the outdated decoys technology but there's no point, everyone saw the research, the audits, is waiting for the code to be complete, will verify it, then it'll be good to run as a new version, no hostility in pushing it out