I don't believe family should ever use greeting cards as a way to be sarcastic. I don't know that your father had that intention at all, but I don't know him. It might be interesting for you to say to him, "Did you pick this card for a specific reason?" Draw him out. People who have a point to make should lay it on the table in plain view and not play head games. (IMHO)

I mean, if you're middle aged, it's hard not to think that comment has a snarky edge to it. But it could have been meant innocently. IDK