While you may be "luckily correct" on that ... it's not a good "rule of thumb" (so to speak). In other words, I'd be less certain about "If this sealant was going to react with brake fluid, I don't believe they would sell it specifically for the threads on speed bleeders" thing. All one need do is observe how many class action lawsuits are out there because a given manufacturer was afforded the benefit of the doubt by customers (Oxycontin, lethal exploding air bags in cars/trucks, talcum powder that causes ovarian cancer, weed killer that causes cancer, high-end Ducati motorcycles with nearly useless rear brakes, et al..). So while speed bleeder manufacturers sell sealant paste, I'd be cautious about giving them the benefit of the doubt regarding their judgement. I suppose I've gone off topic here, but I felt it was worth pointing this out.