You do what you do with all players: you play them if their offense adds more than their defense takes away (well, for bench players sometimes it's just that they are less negative than your other options). In the case of Porzingis and Horford, they clearly do add more. For Kornet and Queta... Not so much, so they're matchup-dependant.
For this specific issue, though, the problem isn't so much the players as how the players fit in the defensive scheme. But that's also not so simple; if the way we defend results in less efficient shots overall, then you have to live with some of those threes. I think the best move is probably to play more switchable lineups when the other team really needs threes, but the majority of the time just rely on the offensive and interior impacts of our bigs outweighing those occasional 3s. When Porzingis and Horford are healthy, I don't think we need to worry about it at all.
Edit: and as for outstretched hands acting as a gun sight, I don't buy it. If the hand is at all to the right or left if the rim then it would make the shot worse, not better, and that would be the case most of the time.