You really need to be at the table, altho the description of the action was helpful. An under-25 internationalist is going to be familiar with many standard deceptive situations, and the underlead of an Ace when dummy is known to be void is a classic, altho I've never had the opportunity to do it. Consider....what holding would LHO have to make clubs a good lead? He lacks either the K or the Q....and declarer is unlimited in terms of his holdings.....if declarer holds AQ, the lead may be a disaster.
otoh, if one holds either 4 or 1 diamond, the chance to induce a ruff in dummy immediately is very attractive.....and there is little downside.
So against a weak player, ruff and hope that both pointed suits are 3-2, but against an intelligent, imaginative player with some knowledge, and the willingness to make interesting plays (and that sounds like it fits the circumstances here)...pitch a heart.....I'd put the chances of LHO holding the club Ace at about 80% and that makes the play better than hoping for 3-2 diamonds.
Of course, a genius defender is a step ahead of me: 'I hoped you'd think that I'd think that you'd think that....'
BTW, I haven't read the companion lead question and will do so now...hoping to see the club A in the leading hand
Edit: having looked at the hand, all I can say is that
'one of the great markers of the advance of human kindness is the howls you will hear from the Men of God' Johann Hari