China can't actually do that without Taiwan making a reciprocal agreement to stop engaging in military buildup against China. Peace requires an agreement on both sides. Otherwise, Taiwan could just build up endlessly and then attack China because it left itself vulnerable.
Let us imagine China started giving Puerto Rico billions of dollars in military hardware. What do you think America's response would be?
China threatens to invade daily, so Taiwan should stop preparing to be invaded? No. Fuck off. China needs to knock it off and stop threatening to invade. Full stop.
Taiwan isn't a potential rape victim, it's a guy constantly telling everyone he'll kill any motherfucker that sets foot on his land and is constantly building up his stockpile of weapons and ammo.
Guys like that often end up becoming mass shooters.
To my mind, it sure seems like Taiwan is like a home owner with small kids who is constantly telling people that their neighbor with unchained pittbulls is dangerous, and then gets criticized for putting up a fence to keep the unchained pittbulls out of their yard.
China is like a rabid dog here, and you're saying Taiwan shouldn't be allowed to defend themselves? Do fuck off.