I (29M) was having a minor disagreement with someone over social media. This other person had the audacity to suggest that people should act civilly and with kindness in the comments of an anonymous post asking for advice.

I took exception to this very uncontroversial opinion by asserting that honesty is the most important thing. I never learned that candor is not an excuse for cruelty, so I proceeded to get increasingly irate with this other person. In my eyes, if someone is willing to make an anonymous post asking for help, they deserve to receive rude answers due to their anonymity.

The other person told me they would no longer engage in discussion with me. They did so in a manner that I found very dismissive and condescending. I became very angry.
And so, even though I am almost a 30 year old, grown-ass man, I decided to look up this person's address and phone number. It was simple to do so on an online contact aggregator using the full name and location I found on this person's public social media profile--I found their cell phone number and their address (thankfully, it's not that person's current address).
I am very smart, so I created a temporary phone number using the app TextPlus. I used this number to text this person a homophobic slur, as well to tell them their age and (outdated) address. All they had to do was shut up, I told them.

Thanks to my behavior, this person immediately changed their phone number and filed over 100 data removal requests to public contact aggregators with their information. I will no longer be able to find them. I, on the other hand, can often be found commenting on AITA posts. I use a username very similar to this one on multiple socials.

Am I the asshole?