I use them both to refer to a kind of unpleasant experience.
While it might be that what you're saying is correct, it's at least plausible that creatures with simple minds--so long as they still perform normal functions--can suffer intensely https://benthams.substack.com/p/betting-on-ubiquitous-pain. So for that reason it's still very bad in expectation.
First of all, the claim that wild animal suffering is serious doesn't depend on the claim that animals suffer more than they are happy. I happen to think human suffering is very serious, even though I think humans live positive lives.
Second, I don't think it's depressive bias infecting my judgments. I am quite happy--actually to a rather unusual degree. Instead, the reason to think that animals live mostly bad lives is that nearly every animal lives a very short life that culminates in a painful death on account of R-selection--if you live only ~a week, you don't have enough positive experiences to outweigh the badness of a painful death.
Regarding the claim that I should be speaking out against factory farming, um...I'm not sure if you've read the rest of my writing.
https://benthams.substack.com/p/factory-farming-delenda-est
https://benthams.substack.com/p/weve-created-hell-its-called-factory
I refer you to my response to Said Achmiz's comment. Do you have a better way of estimating animal consciousness? Sure, the report isn't perfect, but it's better than alternatives. It's irrational to say "well, we don't know exactly how much they suffer, so let's ignore them entirely." https://www.goodthoughts.blog/p/refusing-to-quantify-is-refusing
I tend to think farming decreases wild animal suffering by lowering wild animal populations https://reducing-suffering.org/humanitys-net-impact-on-wild-animal-suffering/