They are simply trying to relate to you. When I tell a person that I stutter and that this may take a while, they invariably respond with “oh that’s OK, I stutter sometimes too.” I have now learned to just let it go and not describe the years of speech therapy/therapy/difficult childhood/shame/trauma/etc. They will have no idea of what you went through and thought by saying this they are being kind. My advice is to let it go. I live in the USA and have encountered this reaction on many occasions.