It really is about tone. Pretend you are talking to your best friend who is usually really smart about things, who you respect. A good hint is not to text when you are tired or grumpy, or out will come stuff that you would regularly censor.
Some people just say things they hear, is their opinion, or have seen it on the internet. They might get offended but just do it nicely and don't argue, it'll be alright. I know I would want to know if I was giving out the wrong info...
There's respectful ways you can let people know they may want to explore blahblahblah because that's the advise you were given. I wouldn't be offended by that, in fact I'd probably appreciate hearing all the different opinions out there if I was the poster :)