Spam is definitely a subjective topic.
Most spam people (and by people I refer to people with a similar mindset to me) find bothersome is less when it fits a narrative and more when its just blatantly the best unit in an army repeated X times and it seems to bother people a bit further when it also pushes the narrative out the window. Yes a horde of trolls may be a tons of units of trolls. But are you using JUST rockguts? or are there bog trolls and dankholds mixed in there? Even if you are not most people would be fine with the spam (even the lore purists would be satisfied with a flimsy but plausible reason for it all) as it isn't spam for the sake of putting power on the table.
Then look at eels. Put down as many as you possibly can fit. Yes it can be cool and the reason people got into the faction (casualties of their interest in specific units in a faction) however we know for the most part its to put the most powerful unit down as many times as possible as the rest of the book "sucks". Same with various other units people complain about (Hearthguards, Witches, thunderers, Terrorgheists, Keepers/morteks at one point etc. whatever flavor people are up in arms about these days) Yea they're cool. But seeing an army composed of ONLY keepers, ONLY hearthguards ONLY witch elves, ONLY mortek with not just one opponent but over multiple opponents in those factions ad nauseum sure does take away from the narrative angle which I think gets to people over time especially those who play against a wide variety of opponents and can see the common trend among most of them. It definitely makes it harder to take your flimsy narrative wrapper seriously when you face the third or fourth guy in a row who "had a larger than usual gathering of keepers all playing nice together for realsies" back at the height of their power and if you google "tournament hedonites list" its the first one there.
yea it definitely sucks to be lumped in with the power gamers who are into winning but that's a risk most people take when they really really enjoy one specific thing. I can't imagine anyone complaining of someones obsession with something like trolls or Steam tanks or Cygors in fact I really love to hear peoples homebrew lore for why/how their specific faction came about particularly when its using something oddball or unique. Really spices up he experience and sometimes it can be very surprisingly adequate on the field.
Don't take this as an attack on people who are in it to win it. Its not what I try to get out of the game and I actively avoid it when I can but its not inherently wrong or abhorrent style of play just not for everyone. Which is why you should always have a chat with opponents before you start to make sure you're on the level.