A sentence thrown on to the end of the conclusion should normally be read as reemphasizing the reasons for the conclusion unless it starts with a word like "though" or "however".
The last sentence should be :
So in that regard, Alpine is less secure by using musl. However, having a small and understandable system is a real advantage when it comes to security.
I'm not charitable, it's just what made sense, like mentally fixing a typo instead of acting like you don't know, and can't figure out from context what someone meant just because they flubbed a letter or a word or something.
I mean, that's just what's called in Philosophy the principle of charity [0]. When evaluating a claim you should read it in its best light, which include glossing over minor inaccuracies and going straight to the main point.
It seems to be they were only comparing the relatives benefits/drawbacks of glibc and musl, but with the way it is written the pro-musl comment feels out of place.