Administered hormones are not equivalent to natural hormones (which is a significant problem with HRT).
And those quotes are not quite "hormones (within natural occurring levels) have very minimal effect on emotion".
"the impact of estrogen on emotion varies"
And another quote from the study you quoted (Effects of testosterone on mood, aggression, and sexual behavior in young men: a double-blind, placebo-controlled, cross-over study):
"Increased circulating T was associated with significant increases in anger-hostility from baseline (mean score = 7.48) to wk 2 (mean score = 10.71)"
7.48 to 10.71 doesn't seem like a very minimal change.
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Since you quoted WebMD (perhaps a useful summary) I will as well:
"It's clear that estrogen is closely linked with women's emotional well-being. Depression and anxiety affect women in their estrogen-producing years more often than men or postmenopausal women. Estrogen is also linked to mood disruptions that occur only in women -- premenstrual syndrome, premenstrual dysphoric disorder, and postpartum depression."
And from another article:
"Declining estrogen levels associated with menopause can cause more than those pesky hot flashes. They can also make a woman feel like she is in a constant state of PMS (premenstrual syndrome). Unfortunately, these emotional changes are a normal part of menopause."
"Some of the emotional changes experienced by women undergoing perimenopause or menopause can include: Irritability, Feelings of sadness, Lack of motivation, Anxiety, Aggressiveness, Difficulty concentrating, Fatigue, Mood changes, and Tension."
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Perhaps we can agree.
I'm not sure exactly what you mean by regulative, but I agree that emotions are complicated and hormones are not the only influence, nor is the relationship a simple cause and effect.
On the other hand, there's significant evidence that hormones do effect emotion, including perhaps the most striking example which I somehow forgot earlier: puberty. And their prenatal effect on the structure of the brain.
Would you agree hormones do effect emotions, but aren't the only factor, and the relationship is complicated, unpredictable, and varies between individuals?