As for the environmental message, I don't know. The plants totally blew away some of the most reliably blue-state states on the map, and then headed for Paris of all places. Maybe Nature was tired of being disrespected by environmentalists as not being able to take care of itself and decided to shut some of them up.
Here's a map, the 'event' didn't even touch any red states, it was New York, New Jersey, and eastern Pennsylvania. I didn't see any loggers going down, and the protagonists escaped in the most gas-hogging vehicle in the movie, a roughly 10 mpg, early 80s Jeep Grand Wagoneer. The plant-whisperer guy got taken out as well.
All of that is in jest obviously, but if you think you'd be irritated by any message in the movie, I would say just watch it to watch it and enjoy the 'what if' aspect of it. It's not great, but it's got some memorable moments.