Not complicated. It means, "you probably wouldn't want to work there."
Interviewing is a two-way street. If your potential employer is intensely interested in your leisure time then that's an interesting signal, because it's unusual (I've never had a single follow-up question to why I took nearly a year off) and could point to a bad culture (lots of possibilities here, including the company being a modern sweatshop or doing very close monitoring and metricization).
That's always important to remember.