Not at all.
Thankfully, my association only does HS, its summer equivalent, and higher ball. Even with that, I will not take sub-varsity games unless my assignor is absolutely out of options--not because they don't deserve good umpiring, but because my game suffers if I have to jump between levels. An example of this was two years ago--I had done a late-season series between two strong D2s (both made regionals that season) then had to do a 10th-grade game the day after. No harm in doing that once in a while, but I really felt out of place.
Personally, I don't know why any game below, say, 10YO needs umpires.