Maybe it's just my own bias, but I assumed the advice comes from people who have been or are lonely, and are talking about what helped them.

The worst depths of loneliness I've had were when I lived in a country where I didn't speak the language well, and was in a tiny, tiny town. The way I got out of it was threefold. One was being kinder to myself. I indulged myself in just being alone. Watching movies on my laptop and trying my hand at creative writing, which I had always wanted to do, but hadn't done. The second was getting into better physical shape. Even half assing it made me feel better: I'm a biologist so I can attest to the fact that one's mental health improves with a little healthier physical body, if it's possible. Finally...I just had to be comfortable being awkward. I was the bizarre foreigner who didn't understand customs or the language, and even when I had assholes being kind of a jerk... Whatever! I just did my thing, went to social events as regularly as I could stomach (once a week ish), and was surprised at how after a month or so, things really did turn around. I found asking questions to be a way to get to know people and places. Other people love to talk and answer questions, even when you didn't ask a question: as we've all seen in this thread.

None of that is to say it will work for everyone, or even anyone else.... But I understand the pain of loneliness. So if sharing my experience can help anyone, please grant me some leniency if I'm being a tone deaf jerk, because that's not my intent!