is that the tootsite very intentionally does not have a quote-tweet button. You can certainly copy the link to a toot and include it in your own toot, but there's no guarantee that it will be embedded inline and there's certainly no UI affordance to make it easy. The intention, and so far the effect, of this has been to cut down on dunking, “look at this dogshit” posts, etc.
Cohost, on the other hand, kind of goes in the opposite direction.
Unlike Tumblr, Cohost has a comment feature that just attaches a comment to that chost without otherwise promoting it. (Tumblr, last I checked, has reblog but no comment.) Commenting is similar to replying to a tweet or toot, but there's no button for it on the timeline/dashboard; you have to click through to a chost's own page to see its comment thread (which has an upside, which is that you might then be induced to read the comments already posted before you write yours).
What does exist on Cohost's dash is a “share” button, with a 🔁 icon like Twitter's retweet button and Mastodon's boost button. This is basically Tumblr's reblog feature!
So share/reblog (air this chost and your addition to your followers) is easier to get to than posting a comment/reply (add your response without necessarily showing the chost or your addition to your followers), and doesn't have the comment thread in the way. Plus you get the ability to attach images to your re-chost, which isn't currently supported in comments.
So far, this seems to have worked out fine—people have been using it for true additions and continuations and the occasional aside comment, not dunks or other hostility. I hope the staff keep a certain amount of vigilance against a dunk culture like Twitter developing, and if it does, that they'll be willing to move the “share” button into the comment thread.