The data was based on behavior between 1999-2014, which means it was behavior that almost certainly was not health motivated since intermittent fasting wasn't popular then. So I think you have to ask: why were these people skipping meals? I think there are a lot of possible explanations and they are all potential confounds.
Like, one obvious reason people skip meals is that they don't have time. If you don't have time to eat, you're probably working long hours and really stressed out. Stress could easily contribute to CVD or otherwise take years off your life.
Another obvious reason to skip meals: you don't have money to buy food. Poverty is well known to lead to worse health outcomes.
Or one more: people skip meals because they have no appetite. What's a big cohort that routinely skips meals because they have no appetite? The elderly.
Maybe they ruled these kinds of things out in the full paper (I've only read the abstract) but so far I'm unimpressed.