The .report mechanism is not a punitive measure to be used by the community. It is an informative measure to help the community help itself. If you do not understand the difference, then that is the first problem to deal with. Just remember, you cannot punish anyone in the game.
Someone having a detrimental impact on the game or the community at large is worthy of a .report. However, it is not and never will be acceptable for lynch mobs to coordinate attacks on an individual using the .report mechanism.
Many people will try to read something into that or want further clarification. The "I want to push it as far as I can" crowd will want more details. Sorry, but there are none. Every case is different. When in doubt, do not report. When in doubt, send us a screenshot or film.
This is not a "law". It is called "community management".