I have often thought the same as andrwhite. thinking about overall handling I'm guilty of- I cradle and ease a trout back into the water. I tend to just place a SMB back in the water unless it was a long fight. This may be reinforced by observation. A released trout meanders and goes away. Some move to the side and rests. Most bass immediately dart off.
a few more theories
as evidenced by another post over which pulls harder, SMB are thought to be tougher, stronger. Maybe if I get some time I'll try to look into scientific evidence that suggests this to be true.
I have often said that we overestimate the fragility of trout- this is not advocating for fishing over spawning trout or mishandling them.
It may have to do with differences in spawning behavior and time. Trout may be more exposed in the low clear water in November. Trout migrated and built beds during a more stressful time and thus are more susceptible to being stressed during spawning
after being disturbed bass might immediately return to the bed. Trout scatter more and take longer to return.
Perhaps we can just see trout better and are more aware?
scientifically, is there a difference in rate of spawning success of SMB vs trout?
Trout tend to be overplayed because of light lines, especially in low Nov water. Bass are landed more quickly on heavier lines
Finally, angler perception and one group being more (or overly, depending on your perspective) conscience. Some of this is sound practice, others not. I guess I'm a control experiment, but an N=1. Same fisherman, just a different behavior and perceptions of the two fish.