Once, when my brother was about twelve, he started singing 'Row, row, row your boat' at the dinner table. One of my sisters joined in, and they performed a nice little round.
No big deal, right?
Wrong. My brother chose to use an alternative set of lyrics he'd picked up from kids at summer camp. They went something like this:
Roll, roll, roll the joint
and twist it at the end.
Puff, puff, that's enough.
Pass it to a friend.
Despite being right next to them and hearing every word, my mom said nothing. She waited patiently for them to finish. Once they did, she drew her arm back and dealt my sister, who was closer to her, an almighty smack to the back of the head.
My sister was quite indignant, having somehow failed to grasp the correlation between her belting out an unsolicited hymn of praise to illegal drugs at the dinner table and this spike in parental disapproval.
"Ow!" she shouted. "Why did you do that?"
"Because I couldn't reach your brother," said my mom calmly.
My sister sulked the rest of the meal. I believe my brother may have gotten a surreptitious under-the-table kick or two from her.
Here's how writing works, in a nutshell: if you have something that you think is worth saying, write it down. If you think it's worth sharing with other people, share it. If some people find what you wrote offensive and criticize it, share it anyway. Take their criticisms into account if they happen to be valid and well-reasoned, but keep on sharing whatever you do. Nothing you write is going to be universally liked by everyone. You have a right to your voice, those you offend have a right to express their opinions, and no one has the right to never be offended ever.
Write anything you want, but don't expect to be adored by the whole world. Also, keep some quick reflexes.
Disclaimer: This post is not intended to defend internet trolls, trashy political 'pundits,' people who non-ironically refer to themselves as 'provocateurs' or 'contrarians,' or anyone else who habitually spews forth vile, hateful crap expressly for the purpose of angering as many people as possible. Getting death threats and suffering legal consequences for being, say, a horrid cyberbully doesn't make you some kind of brilliant, misunderstood second coming of Salman Rushdie. It makes you a wretched fissure in the anus of humanity.