I should have saw the red flag when our first Level 1 adventure was facing a nest of Troglodytes, which each have multi attack of 3, and a stench you need to save from. That was a tough nest, but we did beat it.
Correct, and they have 3 attacks. So 4 of them should be good for a party of 4. But, that is 12 attacks a round vs 4 attacks a round.
They were chosen because they had multiple attacks. Like, what is the scummiest creature I can conjure up for level 1 and have you fight groups of?
I was going to defend the trog encounter, because i thought you were over reacting, but this would actually be pretty tough for a fully rested level 1 party with no AoE or control spells. (attacks at +4, doing 1d4+2 damage on a hit, and having 13HP with an 11AC.)
12 attacks with roughly 40% chance to hit (+4 vs 16AC) is an average of 22.68 damage per round. That assumes they go high enough in initiative to all attack before they die. If they are all top of the order, they probably deal 34 damage total in the encounter if subjected to basic attacks. That's a lot more than I expected. Note: spells, class abilities and feats could reduce that dramatically.
The DC12 Con save is probably a 50% save for most PCs, but more like 55% for anyone likely to be in its range. That means probably 2 PCs exposed and 1 successfully poisoned. A melee character with disadvantage to attacks due to poison usually stinks, but in this encounter its actually not a big deal.
Their defenses are garbage. AC11 means they are being hit 75% of the time, and with 13HP that is probably 2 hits to drop each one. With saves ranging from -2 to +2, they also fall easily to control spells and AOEs that end the encounter in basically 1 round with 65% success rates or better on anything that doesn't target their best saves.
For a party that has access to Burning Hands, Color Spray, Entangle, Grease, Ice Knife, Sleep, Tasha's Caustic Brew, or Thunderwave, this is a pretty good encounter. For a party of fighters and rogues, it will probably end with 1-2 unconscious PCs.
Regardless, I would have left after the first time they said, "oh, sorry. Your PC wandered off with this other group."