While we’re on a roll here, how about removing the ridiculous inline styles from Blockquote tags, and allowing your custom CSS classes to hold their ground?
This one is buried right inside the bowels of the CSS Styled Content standard TypoScript, you can knock it on the head here:
lib.parseFunc_RTE.externalBlocks.blockquote.callRecursive.tagStdWrap.HTMLparser. \n tags.blockquote.overrideAttribs >
The above should appear on one line, without the \n, that was just to fit it in the code window without a scrollbar. I’m pretty confident this is a very very legacy bogeyman that no-one has bothered to clean up, due to the relatively small user-base that requires customisable Blockquotes in the RTE. Either way, now you know.