Seal Defends Perceived Attack on Oprah, Then Blasts Stacey Dash

Seal is making the most epic stance ... against people who think he blasted Oprah, against people who call him an "Uncle Tom" ... and against Stacey Dash. Naturally.

The singer is firing back after getting backlash for an Instagram repost he put up Thursday ... seemingly calling out Oprah for knowing about Harvey Weinstein and keeping silent about it.

We say seemingly, because Seal now says everyone -- including Stacey and FOX News -- got it twisted, and he actually has great respect for Oprah. You just have to watch the video to get his explanation.

Beyond Oprah ... he also has some seriously harsh words for anyone questioning his "blackness" -- and this part of the rebuttal includes him breaking into song. It's tremendous.