Griefers problem

After the introduction of overwatch, there has been much more griefers and game ruiners, before that I rarely saw these in my games, but now they are much more common, I fell like the whole overwatch thing is just made to make ppl feel that there is less griefers and that they are punished, the worst part is that these ppl are not in normal games, but in ranked and they lose other ppl mmr purposely, it also seems like behaviour score system stopped working, Im a 10k bs legend player, and I have seen over 12 griefers in last week, 6 of which happend in my team my last 6 games:

Game 1, match Id: 5912076961

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Our support pick sniper, he was creep during laning stage, leeching xp and roaming around map, then Ta ragequit and abandon

Game 2, match Id: 5912174986

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Mk, was feeding, at the start it looked like he was trying, but we realized that he is not legend player and probably bought this account, then after his 9th death he abandon the game

Game 3, match Id: 5912332654

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Our offlaner picks lion, and at the end we lost becouse we had no offlaner, just 3 supports, lion died to fast, he was only able to cast few spells, there noone had aura items like greaves and pipe, that we needed this game, we also didnt had a proper offlaner to hold enemies and protect our mid and supports, lion made aether lens, and was playing like a support

Game 4, match Id: 691244022

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Bristle lost his lane and started running down lanes feeding

Game 5, match Id: 5912569757

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Our offlaner picks phantom lancer, feeds troll, buys divine rapier later, he made about 12k damage in a 50 minuted game, also I had the most damage in our team, about 32k, silencer and pa had about 24k each

Game 6, match Id: 5912680008

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Our first picks are 2 backline heroes: zeus and visage, enemy have 2 long range disablers: luna and lion, then our offlaner picks enigma, then after enemy team picked bristle and jug, our mid picks medusa, and our pa builds battlefurry, I will also mention that pa didnt buy magic stick vs britle luna 4 lane

Idk why are there so many griefers, I have seen many mostly in my previous games, but now when this 6 loose streak happend to me I started thinking about it, as I said earlier, this increase in griefers happend after the overwatch update, I feel like this system is not working, also the amount of avaitable reports is too low compared to amount of griefers.

Pls tell me what you think about it in the comments, also here is my dotabuff if you are interested: 195163100