In the early 80s, the Federal govt told the states to raise their drinking age to 21 or...

[Yavin4]

15. Understand this.

The drinking age directly affected the safety and cost of the Federal highway system. It followed that states could (should) be required to clean up their acts in the area in which their behavior impacted Federal funds.

States that do not mandate wearing a mask directly affects the safety, health, and cost of Federal employees whose healthcare is paid for by the Federal govt. For example, in FLA, there are several military bases in that state. If the state's community spread hits key military personnel, that's a threat to our national secuirty.

Masks or no masks do not directly, or indirectly, effect the Federal highway system so it "does not follow" (non-sequitur) to withhold HIGHWAY funds for such. Perhaps health funding which directly relates to it, perhaps yes.

A no mask policy makes all Federal employees -- which incldues military personnel -- vulnerable to the virus. As such, in order to maintain the continuation of services and national security concerns, the Federal government has the right to withhold federal funds from states that put its employees and contractors at risk.