That's going too far. It's almost like saying "don't fight a battle that won't immediately win you the war." It's important not to overstate their effectiveness (an export ban won't hit some Achilles heel that grind their military to a halt), but that doesn't mean the short term effects aren't valuable and the right thing to do. These bans are delaying tactics, they'll make things harder but not impossible for Russia and China to do certain things, and they might have to make unwanted compromises (e.g. force short-term supply chain issues and redesigning using a less robust common civilian grade chip they can get on the grey market rather than the harder-to-get specialized chip they want).
Basically, don't let the perfect be the enemy of the good.