There are inherent limitations with click activity. It’s not possible to click 2+ places at once as a person, so how would a robot or other software do it?
If you are talking about click + drag that a mouse does, then yes that’s possible, but wouldn’t be great to have a robot do it. Too much variability on how many pixels the mouse needs to be dragged, etc.
If you are tlaking about selecting multiple items sequentially, how does a person do it today? If it is click, ctrl+click, ctrl+click, etc. Then why not have the robot replicate that? It should be so fast that it seems instantaneous if you are able to use simulate click for this. Still quite a bit faster than a human if you use the normal/standard hardware click with the robot.
As Clayton mentioned, if you’re just looking to select certain items, that’s different than clicking, and it is certainly possible to select 2+ things at once, but that depends on the software you’re interacting with and the specific items you are trying to select.