In the short term, the argument that by voting for this party rather than that party you will make things worse is often true. It’s also sometimes true that by voting for that party rather than this party, things will get worse more slowly. But that may not be the point.
“If you think we’re bad, look at the other guys” isn’t, and never has been, an acceptable argument. As I said earlier, if a system is broken, it’s broken, and it needs to be replaced as quickly as possible. History suggests that the longer a major change is delayed, and the more it is resisted, the more violent and the more traumatic is the change when it comes. Voting for a party because they are “less bad” than the others, sounds sensible, but only if the situation is actually recoverable in some form. If it isn’t, then it’s a false, and possibly dangerous, tactic.
But what do we mean in this context when we talk about “change”?