I think that I understand how you feel, because something similar happened to me in another forum - another poster must have misunderstood what I had said (all in goodwill) and starting swearing , name-calling, etc at me.
Really surpised me - but, I figured that - the reaction was immature, and kind of inappropriate.
And I agree that what is written (because we now have this internet method of communication that is unlike person-person), will leave a person open to misinterpretation. And that misinterpretation will allow the reader to introduce their own attitudes.
Try not to feel too badly about what happened, as long as you didn't mean any harm - just try to understand it. The person who is reading may be dealing with a lot of other stuff that you don't even know about, and that'll get mixed in with their interpretation.
Here's a hug for you - hope it helps a bit.