You can't tell some young guys anything!

I'm trying to tell a young mechanic about T4 Rotella and to put it in an older truck engine at the shop a 1990 4.0 Jeep six cylinder..Nope that's for diesels only..No way should I be putting that in any gas engine. https://www.amazon.ca/dp/B01LH7L0D0/?tag=joeychgo-20

Is it good or am I the idiot in this argument?

Hmmm... sounds like my six year old, he gets very excited when explaining. But he's six!