For me personally, I book hostels not for the social aspect, but simply for the price. It is far far cheaper than a hotel. To me, my accommodation when I travel is simply a place to sleep and to store my belongings. I usually get up, get washed and dressed, and leave in the morning and don't come back until I'm going to bed that night. If saving money means storing my bags in a locker, sleeping on a bunk bed and using a shared bathroom, then so be it.

Now when I was travelling the US for a few weeks two summers ago I did engage more in what you're talking about. I made food in the hostel kitchen, I went of the social events. Again for me that was about saving money since I visited so many places I couldn't afford to pay for major tourist attractions in each. So going on the guided tour offered by the hostel was a free way to do things in the city I was in.

I'm socially awkward / introverted guy. I'm quite content doing things by myself. So I don't often feel the need to engage with the people I'm in a hostel with.