Only explanation I can think of is that the timeline doohickery advanced Gero's technology and powered up the present androids allowed him to modify them nowhere near as painfully as the ones in the future, making them less evil
correct answer of course is that didn't think that far and doesn't like to think
I tend to go with #17 saying Gero programmed them for world conquest in the OVA. Since Goku was already gone, the idea of Gero reprogramming them for that purpose makes sense.
Plot reasons, the Z-Fighters know about the Cyborgs arrival and so they train and thus making the Artificial Humans more powerful at the cost of their wicked personality.
Well, after Cell was defeated, the Androids were no longer the top dogs, so they couldn't do anything bad. Before that, i don't see why they
couldn't be as evil as the ones Trunks knew. Seventeen even declared he would kill Piccolo in their second fight.
The first time i watched the series, i wondered why they didn't kill Z fighters in the first fight. In the end, i deduced it had something
to do with Sixteen's presence. Also, we don't know when exactly the Z fighters were killed in the original past.
The Present Androids were chill the entire time. #17 did mention possibly causing trouble to draw Goku out, but nothing ever came of it. The Future Androids just wanted to exterminate people for points.....
Maybe in the future, Gero taught them to control their new powers playing Fallout. They then immediately copied what they saw (on him) and went on to repeat the process with everybody else
Who's to say they weren't? The androids only spared Vegeta and the other Z Fighters in their first fight as part of a game not because they were being merciful or the like. Afterward, #18 after seeing just how kindhearted Krillin was by refusing to kill her and trying to protect her from Cell began to soften up (like Picoclo with Gohan) and #17 really can't do anything with how weak he is compared to the Saiyans and even Piccolo by the end of the Cell Games.
#17 telling Krillin to feed them senzu's before they die is as merciful as one can get. He didn't even care about fighting them again. All I recall him saying is they can challenge them in the future if they're up for it or something along those lines. Finding Goku was "the game", not fighting or sparing the others.
The most they did was peacefully take a van from those guys and #18 casually stopped the police car with her fist when they were being chased. The Future Androids would've killed all of them and counted it towards a score.