People who intentionally farm small camps while team is doing objectives

in the last 2 weeks I met 5 people in different games who either feed early or/then complain about another lane/ lost their lead and tower and consequently objectives like dragon and baron. they then proceed to spam /ff even though we're well ahead. Then they all intentionally go for small camps or slowly farm lanes. How intentional are they? well, a team fight erupts because of the said types of players, the team helps save these players, then instead of going back or turning around for team fights, the said players go into another lane/camp farming until they die either by minion/camps/enemy. They do this on repeat again and again. all the while refusing to buy any items (possibly due to them dying more than they farm). What's worse, they take jungle buffs they obviously don't deserve, and the jungler can't do anything because of team fights. then they donate said buff to the enemy and bait teammates because they keep going into dangerous situations.

What should I report these people by? "refusing to communicate?" technically they are communicating... they just say the nastiest toxic things and blame other weak lanes :/ "unskilled player?" technically they are not bad mechanically and game knowledge-wise because of how well they know to intentionally throw the game. "negative attitude?" but this doesn't adequately describe how toxic they're being. Keep in mind this occurred in 5 separate games over 2 weeks, not including the other toxic players who are still somewhat helpful. How is league becoming more toxic? For the past 2 years, I've encountered 2 other people who acted like this, but now 5 showed up... am I incredibly unlucky or is THIS becoming a thing?

Edit: Keep in mind these guys in client and during the first ~10 min don't seem like bad guys at all (they offer to fill and don't complain about niche picks). But if they go negative KDA in the slightest way at anytime after 15 minutes they turn on total dick mode. (3 of the 5 guys are adcs, the other two are top and mid)