Spit on a random place on a blank wall and come back in a week. I bet you'll be able find where it was (despite evaporation)... because spit isn't just water.
To be clear- I do not think masks are 100% effective... but they help. (Depending on the mask of course. The "plandemic" mesh masks they were selling in 2020 surely did nothing and idk about the cloth or crocheted ones)
I typically use n95s indoors in crowded public places (not the ones in your meme) because the surrounding edge fits better on your face. If there is a gap, clearly the mask will not filter anything between it.
Also... To go back to micron size........OSHA claims that when worn properly, N95 masks can filter particles both larger and smaller than 0.3 microns. So even if it was a Covid particle 0.3 microns in size attached to whatever was left of a spit particle that had the water evaporated out as it exited someone's mouth and traveled beyond their unmasked face to you......... theoretically an N95 mask should be able to filter it out... (Unless OSHA's website is lying? Idk)