I always thought so too. You see it from time to time in other Yuri where you have someone watching over the couple (usually a guy) from a far and it always made me feel a little uncomfortable. Like I guess maybe it is fine if they are a close friend as long as it doesn't get taken in excess... but I personally really would prefer to be left alone if I'm on a date with someone unless it is a double date or something.
And what if the two people you are shipping together end up having no feelings f or each other and are just really close friends (or sisters?) Well now you just made things super awkward.
I guess maybe it is supposed to be an allegory for the readers... but there is a huge difference between reading a fictional story of fictional characters getting together, and actively watching real people who are in a relationship who have not given you their explicit consent to watch them