Interesting perspective that would never have crossed my mind.
I love this format because I've been on internet forums since dial-up Compuserve 30 years ago and find the new social media format difficult because it comes across to me as chaotic and unorganized.
It's all what you're used to.
When you want to quote an entire post you can use the quote button at the bottom right. When you want to quote a portion of the post you highlight what you want to quote and hover for a moment and the quote button will show up.
At least that's how it works on the desktop. I only very rarely use this site on my phone because it's too small for my aging eyes.
The quote button clips out the text you want and stores it until you get down to the bottom, where you'll find the option to insert quotes in the reply box.
The reply button jumps over all the other posts and takes you straight to the reply box with the quoted text automatically inserted.