Unless i completely misunderstand their "slang" it appears that you could be taxed differently for reg income and for cap gains.
That's correct. I may have misunderstood what you were saying in the post I quoted.
So yes, the rates/brackets are different between regular income and cap gains, but cap gain rate depends on
total income, not just on cap gain income. IOW regular income can push you into a higher cap gain bracket. Cap gains can't push you into a higher regular tax bracket. But there are other hidden costs (e.g. higher total income may affect eligibility for some retirement contributions).