You don't necessarily up/down people on HN because you agree or disagree with them. It's about contributing to discussion.
Sadly, asking questions is apparently considered "not contributing". Very friendly.
It depends on the question. The parent poster obviously closes his browser, otherwise load time wouldn't matter for him.
Furthermore, your question calls for a yes/no answer, which is hardly contributing to the conversation.
As for the why he closes the browser, I don't know. Maybe RAM scarcity... But it isn't wonderfully interesting to have that kind of anecdotal conversations here.
I don't disagree that applications (and operating systems) should start up quickly, but it hardly seems like a critical complaint. And, as much as I appreciate improved Javascript performance, the differences are not that significant in the real-world.