They look star-shaped because of refraction on the atmosphere and in our eyes. Those telescopes just have way larger relative distortions because they do have larger distortions and can see smaller things.

there are a series of things that can make points of light look spiky: eye defects, eyelashes when squinting, smudgy glasses, etc..

People have indeed thought this before telescopes. You'll most likely see diffraction patterns around bright lights because of eyelashes and other imperfections, probably different for each eye but the same for all lights (technically, wavelength also matters but not really on this scale).

I’ve always wondered this. For now I’ve settled on the hypothesis that all the first astronomers all had astigmatism.

Have you looked at its other side?

Yes, that's the problem