Basically, what it comes down to is that if all 37 requests are done in parallel, then you're only loading the page as slowly as the slowest. Sadly, this is rarely the case. Most browsers will only make 6 concurrent requests from a server, which you can see in Firefox via the about:config page and the network.http.max-persistent-connections-per-server. Worse, some of that JS is probably downloading more JS, which means that you will have multiple requests going out.
On mobile, this means you're running 8-30 second delays for each "group" of requests, especially if you have poor reception. Good news is that after that initial latency, the actual transfer should go fairly fast.
On the other hand, a social commenting program should need at a minimum 1 JS file, 1 CSS file, 1 for the actual data (3 comment texts, 3 base64 encoded profile pics at a small resolution). So FB is running at ~30x the optimum (87 assets, of which 35 are JS).
If you think it's not that big a deal, I'd suggest taking a trip abroad or just out to some smaller towns in your area, and really experience why users feel the internet has not really gotten faster since the 90s (keeping in mind users don't care about data size, they care about latency).