Including that sentence doesn't make the fact that it is undisputably a two-ways street go away.
If it's an honest mistake, sure, don't get offended. But if the person does it on purpose, then we're talking about something else altogether and there's no reason to simply "don't get offended". In the later case I'm not offended by what I'm hearing (the person who's going to make me feel inferior ain't born yet) but I'm offended by the fact that the person is trying to be offending on purpose.
There's a very easy way to be sure, you simply gently ask something like: "Are you trying to be offending?"