6e never said you can't snipe spells at physical targets while you're astrally projecting. 6e only prohibits this while you're
manifesting. "Clearly", the intent is that the prohibition should also include projecting while not manifesting. That's an example of where the "this is how it worked in 5e" rationale is reasonable.
I'm going to say that Touch range spells is NOT one of those cases. 6e explicitly breaks from prior editions in a couple ways, and that makes "well this is how 5e did it" particularly unreliable due to those hard breaks.
in 6e:
Direct combat spells are resisted by rolling WIL + INT (a hard change from prior editions)
Indirect combat spells are resisted by rolling REA + WIL (another hard change from 5e)
per page 131, this is what we know about how Touch range spells work in 6e:
(Touch Range), meaning the target
needs to be touched in order for the spell to
take effect (when touching an unwilling target,
make an unarmed Close Combat attack, and
subtract the target’s Armor rating from their
Defense Rating for this attack)
It doesn't say whether this is in addition to or in place of the standard Sorcery + MAG test as normal for delivering the spell.
Logically the possibilities are:
1) it's in place of
2) it's in addition to
3) neither of the above
I don't think 1 can be right, as the Close Combat skill is only establishing that a condition for casting the spell is met. Ultimately, the spell ought to still be cast via the Sorcery + MAG test. And, in the case of combat spells, you're going to compare AR to DR AGAIN for the spell itself, anyway. But, acknowledged, option 2 slows the game down by adding another test to the process of resolving the action. But, since both spells are resisted at least in part by Willpower, I don't have any "suspension of disbelief" problems with why an indirect combat spell might still "miss" after a touch was successfully established.
3) is an interesting wild card. It's probably the realm for where house rules would go that rely on logic that is not present in what the 6e rules establish. Something I could see as being completely reasonable is similar to what Xenon suggested in a different context: make one test but use the lower of the two involved skills. Use the lesser of Close Combat or Spellcasting + MAG to deliver a Touch range spell in one test. I don't think there's solid grounds for that to be an official take, but it's absolutely a fine way to run it for your own game.