lugubre

Nah... I'd call and expect to win 40-45% of the time.
In my opinion Festivuss is quite likely thinking that YOU are only calling with a J in your hand, despite your riverbet which appears to be to big for numerous reasons. If he arrives at this conclusion he likes your too big river bet even better (since it will win him even more chips if you fold).

His range is so wide here and yes - he might have a J or even JJ. But he could have almost anything as far as I see it.

If you are better than the average player, you want to have all the chips you can get from the start since you would be more likely to accumulate. You want to have all the chipps you can get behind when you flop a set of 3's against a guy going all the way with AK if flop comes A83 etc.

Furthermore the deeper you are the more hands you can allow yourself to play due to implied odds when hitting.