First or second class for a sympathy card?

[Sug4rRush]

It seems like such a trivial question but I can't decide: is it insulting to send a sympathy card 2nd class?

(The reason I ask is that I have 2nd class stamps in the house, but I'd have to make a trip for 1st class)

No. If you want to send if first class without making a trip, just put two second-class stamps on for it.