can you leave your hand hold things down in the TSX like in the 2nd gen tl:

 

Nope, they go back up (slowly) when you let go of them.
Odd question, why do you ask?

 

What would be the advantages of leaving them down even if it was possible? I can think of a major disadvantage already - bonking heads upon entering or exiting.

 

Very odd question, dont understand why you would want to leave them down.

 

I've seen girls in mercedes benz with their dry cleaning hanging down from all 3 other doors (how she saw cars around her car, I wouldn't know). But if that were the case, the hangers should hold them down anyway.

Those handles are only to assist the passengers as they get in/out of the car. Leaving them down like that in the picture makes it look ugly. It's not a truck...