Iv'e noticed this happening as well so i ran some tests of my own, its usually youtube's algorithm that detects the videos as spam and not flaggers.
From my tests the main thing that cause these quick/mass bans are
1. uploading videos as unlisted
2. shortened/hyper linked links in the description (just watermark your video, if you add a link to the description make sure its not hyperlinked for example you can write www.example.com or example.com (links like that wont be hyperlinked) but if your link starts with http then it gets hyperlinked and gets detected as spam fast.
3. nasty list of keywords in description (aka shitty keyword stuffing that used to work back in the day)
4. uploading only how to/free download videos onto your channel (I make sure every 1 out of 5 videos I upload is a random gaming video type thing)
(Extra tips that will help you)
1. while uploading the videos just name them the game title gameplay, example: dayz gameplay. Then rename the video after a few hours to the title you want.
2. I also leave my description mostly blank until after a few hours of upload, Then I add a good article that is spintaxed so its always unique and helps with ranking and getting authority to your channel so it would stay alive for months/years.
3. dont upload a bunch of videos on to 1 channel in 1 day, what i do is i upload 5 videos a day to 10 channels, so i upload 50 videos a day for 4 days (total of 200 videos a week) then i rank the videos for 3 days, then as the next week comes along i rinse and repeat with new channels.
4. I also upload a few stock videos to my channels and add legit looking interaction onto those videos/channels about a week before using those channels to upload tutorial type stuff, what that does is make youtube give your channels a bit of authority so videos rank better and your channel seems more legit.
5. once you learn to create good authority channels then youtube mostly ignores any flaggers on your videos.
ps
I also do the gaming niche and by doing what i told you ^ up there, I haven't had a channel ban since september, it seems like a lot of work but i was able to automate every thing with some stuff (MVB Pro, and I made a yt ranker bot that shares/likes/subscribes/favorites/comments my videos with 350+ channels). Any way just make every thing look natural and yt wont ban you (as much). Good Luck OP