There is a big problem in the everglades with pets that have been released. Pythons are an invasive species down there and are really messing up the alligators so what they say is technically based in fact.

http://news.nationalgeographic.com/n...vespecies.html

Side note, you won't cause any environmental damage by keeping a snake. Releasing it (if you live in a climate that would allow them to thrive) would though.

On to the main point, don't let it bother you. People will say what they say and only time will allow them to see that they're wrong. Just let them live in their ignorance and let it be.