If you're not trolling, you've genuinely just misread the room. One of them just said "I'm guessing this is irony." and surely you would agree that your first comment was ironic? You were using irony to mock the downvoters, you don't actually think "How dare you propose a healthier lifestyle instead of a machine or app to solve this problem", as you clarified in your next comments, but to strangers online who don't know you they have to guess (or, as they did, ask) whether you're being ironic/sarcastic or not.

It's incredible you can interpret somebody asking if you were being ironic - in response to a comment you wrote intentionally to be ironic, but without making that clear - as being "passive aggressive".