Putting “just saying” at the end doesn’t turn rude into honest. It just adds a signature.

A tag at the end does not retroactively change what came before it. Adding one signals that you know the line was sharp and would rather not answer for it, which the listener hears clearly, so the effect is the sting plus a little evasion. Honesty does not need a disclaimer. If a sentence needs protecting, that is information about the sentence.

Say the thing without the tag or do not say it. If you meant it, own it and be ready to discuss it. If you did not quite mean it, that is a reason to rewrite rather than to add a signature.