Well, you can't really argue with logic like this. Of course it's the fault of the guy who hadn't been president for over a year who wasn't the one to start a war without any preparation.
something to consider...first of all, you're right about starting a war without having the weapons inventory necessary is kind of dumb.
But, here's the thing, we have been discussing China and Taiwan, and the possibility of defending Taiwan for years.
It takes years to produce weapons (3 - 4 years for patriots) so given the possibility of war with China, we were woefully unprepared. And that lack of preparation goes back a lot further than just Biden and the congresses during that administration. Underfunding weapons procurement has been a thing for multiple years and through multiple presidents and congresses.
There was a war game, either late in Biden's term or early in trump's where the end analysis was that the US would run out of missiles in 7 days. You can't make up that deficiency overnight.
The blame, if you want to call it that, has to fall not only on politicians, but the Pentagon might well also some part of it, both for not including more weapon procurement in their budget requests, for failing to adjust to modern warfare need (like drones), and maybe for placing emphasis on the wrong things in their budgets.