To address the OP, I'd like to share a few things.
So did the player who owns the chemists counts as someone who "worked hard"?
Okay, so maybe not quite as hard work, but leaning closer to "thought differently", by the other guy's admission.
And yes I also saw the same 6 chemists in Rachel Sanctuary when I was fooling around with that Hylozoist + Baphomet card (I wanted to test if it works in dungeons. Answer was no).
It's not fair for anyone to ask that you stick to the "conventional" way of farming, but I'd like to point out that, unlike Abyss Lake or any other tough dungeons, Sleepers map is something that draws in way more people than the aforementioned maps, and you get to bump into quite a lot of people who also wanted a piece of the place. Same deal with the other two popular spots (Geffenia, Moscovia 3).
You've seen the rules. They did ask that Homuns be parked someplace out of the way, but we're talking about Sleepers map: nothing is out of the way when everyone's trying to take what you can. So I can understand your confusion when someone asks you, although in a nice manner, to tone it down a bit.
Here's what I think: If your chemists can kill sleepers fast enough, then I don't think it's gonna be as big of an issue as it is right now. Maybe some people wouldn't mind it as much.
Compare these 2 statements:
6 Chemists killing 2-4 Sleepers each.
6 Chemists taking a long time to kill 2-4 Sleepers each.
If you're not holding down the spawn (say something crazy like Amistr or Lif with bad stats, or any homun with bad stats), then I think some of the OPs concern can be alleviated. Maybe not by much, but it's something to consider.