I'm not sure if some of Tumbler's user-base knows this, but you do know that if there is something you want to add to a post that's related to what they're talking about, you can do that without insulting them in the process.
I keep seeing comments and reblogs around Tumblr along the lines of "wow, all of those words and you didn't even bother to mention x 🙄".
The thing about replies like this that there's a strong insinuation that either x was left out intentionally and maliciously, or that the person writing the post is an idiot for not already knowing about and including x, or both. Either way wording it this way is an insult and a put-down to whoever wrote the post.
Maybe sometimes people didn't mention x for malicious reasons, but 9 times out of 10 that's not the case. Most of the time people either generally didn't know or weren't fully aware. Or maybe just genuinely forgot. Either way, it's not called for to insult and attack people who are total strangers to you on the internet.
And there really needs to be more emphasis on the whole "people on Tumblr are strangers to you", it's rarely called for to attack or insult strangers unprovoked. Say some of your new co-workers or classmates you haven't really gotten to know yet are talking about how your city is going to be getting rid of some of the bike paths, and one of them is talking about how this is bad for the environment. You (hopefully) wouldn't butt in and say "wow, all those words and you didn't even bother to mention how this affects lower class people who can't afford cars 🙄😒" and if you would actually do that, you seriously need to work on your boundaries because it's really inappropriate to just attack and insult people unprovoked like that.
Of course you could say something like "oh it's not just an environmental issue, this is really going to hurt lower class people who can't afford a car!". You can actually just add it in a neutral way like that without attacking or insulting anyone in the process for not already saying it.
People become more closed off and less receptive when you attack and insult them, btw. Even when you're saying something they'd otherwise agree with. In some cases I wouldn't count it against someone for attacking and insulting someone who is genuinely being cruel and malicious, sometimes it is called for and can be a form of self defense. But just over someone not knowing something or forgetting to mention something? What do you actually gain from that?