readability: to what extent is the blank text on a medium to light gray background objectively a bad practice?

I made the mistake of openly criticizing a web page because they asked me for an opinion. I ruled negatively. To what extent is the designer guilty of my unfavorable criticism?

Legibility judged objectively?

Here intrinsic and external factors intervene, such as monitors and eyes.

The small text, from 8 to 10px, white, in a solid tone of gray, which is somewhere between 10 and 35%, still made me fall a "star" … probably because the LCD helped me. The viewing angle of the screen, the density of pixels, maybe even the reflection of the screen could have influenced me. However, am I to blame or is this supposed to be avoided?

Since I have a slight astigmatism, I should not appreciate small sources that are too thin or light. But actually I use this configuration at this time for my desktop environment, with supbixel processing enabled as a necessity to render the font correctly, it is very thin. I'm not blind

Is it sustainable that one should not have to weigh such external factors, if one adheres to good practices, as a greater contrast between the text and the fund?

There was also no real need to choose such a clear gray. What finally gave me the impression of being careless, while the author could have tried to keep things warm and cozy with his choice of colors.

Relevance issues

The thing is that the user is not reading a poem with this configuration. I'm talking about the menu items that will only be read really until the user learns instinctively in the third word of the row.

Personally, I think readability is important. But good practices are not rules and I can not penalize the author because he violated Article X. Is this still somehow objectively A misstep from a UX perspective or is it rather that I was prone to simply "finding fault" subjectively, frustrated by not being able to read some words at a glance? To what extent is the white text on a light gray background objectively a bad practice?

Bonus question in the same line:

This menu was also hidden unnecessarily from the view, until it was invoked by a click. This superfluity made me fall another star, since it gets in the way of efficient interaction. Except, it's just an additional click. However, making a furore in the dynamics for the sake of having dynamics can be done without getting in the way.

The same question. Did I hold a valid resentment? Should the author get it or rather be offended?