Hiya!
Just to help me understand.
1. Your table roll for ability scores.
2. People get upset when someone rolls well and is too powerful.
3. The DM then conspires to kill them off.
4. The player is upset, for the root cause of having rolled well on ability scores and therefore getting targeted.
If I was at this table either as a player or the DM, I would strongly push for point buy or standard array. This way people don't feel put out when others roll better than them, and others don't get targeted for the crime of rolling well. It seems the table doesn't handle random variation in a mature way.
1. Yes, generally speaking. We used the 4d6 drop 3 'standard' at the beginning. We did have some rather swingy characters in the group (the Goliath was with a...gnome I think?...who had horrible stats. It was amusing, but with 5e's design around stats being so important, once everyone got to around 5th, it really became painfully obvious. I came up with my "Wheel of Pain" method of stat rolling after that. The player in question was "annoyed at having died", sure, but he wasn't "upset at how unfair it was".
2. Nope. Nobody got upset. We're a pretty mature group and if one guy is more "powerful" than another, so be it. Nobody cares from the perspective of "but I want to have awesome stats too!!!!....it's not fair!!....". One thing that I use/enforce at my table and have been for decades, is that when your PC dies, you make a new 1st level one. I did make an exception for 5e; now it's "average party level -2; maximum starting of 3rd".
3. I didn't conspire to kill any PC's off. I design my adventures without much regard for the actual PC's other than the most basic of things; average level. I get a story/idea, draw or get a map, then start "stocking the dungeon". I usually use the basic D&D 'stocking the dungeon' tables where you roll 2d6's. IIRC, the particular dungeon they were in was an old, abandoned dwarven citidel (I think the maps were called that; "Dwarven Stronghold" by 0one Games off of RPGnow.com). I think for it I used a mix of basic D&D stocking tables as well as the random stocking tables found in the 5e DMG. I used the "Monsters by CR" as a base to determine, randomly, what monster was in an actual room. The dungeon is rather large, with several levels, so it had a good range of CRs. The Intellect Devourer wasn't my idea...dice roll what dice roll. And the PC's were on one of the lower (lowest?) level.
4. Nope again. He wasn't "upset" in the manner that you are probably assuming. He was more 'annoyed' that it was bad luck on his part to be the one who rolled the 'target' of the ID. Usually, when there is an equal opportunity for all PC's to be targeted by something particularly 'nasty'...I make the players roll for it ("Dice for Death?"

). The ID was undetected, naturally, and could have targeted any of the PC's. I have them all roll some dice (d6 is common, as well as d8 and d12)...lowest roller is the target. Ties, they roll between themselves with lowest roller being the target. In this case, the Barbarian with an Int 6. I rolled the attack, rolled the 'damage', and that was that. A brain dead goliath barbarian that nobody in the group could carry out, let alone have the damage be 'restored'.
I freely admit to being what would nowadays be considered a "Killer DM". The mountains of dead characters that line my throne room is vast and ever-expanding. But, other than a VERY select few; like, maybe two or three over my nigh-4 decades of RPG'ing. Other than those two or three I mentioned (and yes, they deserved it), I do not "plan" on killing a PC. Running a D&D game 99.8% "neutral"...there will be death of PC's. I don't have to do anything other than do my job as the neutral arbiter of the campaign world.
Hopefully that clears it up a bit.
^_^
Paul L. Ming