I'm a straight, cis man who pays attention to how women look in their makeup. It has nothing to do with being misogynistic or wanting to shame women, and is much more rooted in what I personally find attractive and my 40 years of experience of being in relationships with women. When you've been around a woman in one shape or form your entire adult and teen life, you're bound to learn a thing or to.
Now my having an opinion is not the same as trying to belittle someone or shame them or make them feel anything one way or another.
In fact, unless I'm talking about it with my wife (who is a makeup artist) in private, or I was giving constructive feedback on someone I was involved with that something needed adjustment (I might say something like “Baby? You might consider blending that a little better“), I won't say anything at all.
Perhaps it's the aforementioned 40 years, or it's my being married to my wife for 12 years and it's heightened my awareness, but yeah, if a woman's neck is several shades darker or lighter than her face, or she's wearing "night out on the town" levels of makeup at noon on a Tuesday, or who's foundation is so thick that it is visible in her smile lines, then yes, I'm likely to notice. I won't say anything, but I'll notice.
Just like when I go out in public, people are going to look at me if I'm unshaven (which I am sometimes), or I haven't put lotion on my legs, or I'm sure they notice that I'm not as svelte as I once was. We live in a society where people notice your physical appearance, though I completely acknowledge that those expectations are disproportionately applied to women.