As has been mentioned in the question, since most of these individuals are not discerning between good and bad, they have the same ruling as insane people and there is no need to wear hijab in front of them.

Of course, it is clear that if someone can discern between good and bad, then it will be necessary to wear it in front of them.

Notes:

These are the responses of the offices of the maraji' regarding this inquiry[1]:

The Grand Ayatullah Khamenei (may Allah prolong his life):

In any case, if he isn't considered insane, then it is necessary.

The Grand Ayatullah Sistani (may Allah prolong his life):

If he isn't discerning then it isn't wajib.

The Grand Ayatullah Safi Golpaygani (may Allah prolong his life):

If he isn't discerning then it isn't necessary, although being able to expose more than is normative isn't permissible.

The Grand Ayatullah Makarim Shirazi (may Allah prolong his life):

In the case of the question, if he can discern between good and bad, then one must wear the hijab in front of them.