Coutinho made the switch to Camp Nou as recently as January, joining Suarez who signed for Barca back in 2014, but the pair will watch on television as Liverpool face Real Madrid in the Champions League final on Saturday evening.
Henry has questioned why the South American chose to face "weak opposition" for much of the La Liga campaign, as well as acknowledging that both players would have started for the Merseyside giants in Kiev.
The American businessman told The AP: "Maybe it's because I'm an American, but I have a difficult time understanding why anyone would want to leave Liverpool. The club is so rich in history and tradition, supported by so many millions around the world, in virtually every country of the world.
"You don't want to be in the position where players want to go somewhere else, even if it is a great club like Barcelona. It's hard to understand why players would want to go to a league where the competition is so weak. They must play 30 or so meaningless matches per year waiting for Champions League matches.
"They'll be watching this weekend and could have been playing."
Suarez scored 82 goals in 133 appearances for Liverpool, while Coutinho netted 54 times in 201 outings for the North-West giants.