>Someone in ICE uses Microsoft Excel to maintain a list of people who they believe should be send to an internment camp. Therefore Microsoft is an accessory to that?

Utterly disingenuous. Surveillance software is primarily sold to governments to spy on individuals. It doesn't exist for any reason except for the powerful to oppress the weak.

>Where do you draw the line?

"I just kept turning the heat up and the frog seemed perfectly fine. The fact that it's cooked now can't have anything to do with my actions." I don't have to propose a generalized demarcation criterion to say whether a particular example is on either side of the line.

If Microsoft sells ICE a subscription to Office then yes.