He has no right or ability to force you, but you know he has every right to tell what he thinks ought to be done. You have the same right, and have done so in the past, advising people on the virtues of not voting. If that was all with a better demeanor, well – instead of just complaining about the reception, you should take a look at what you actually jumped into.
Cowicide had provided not just an opinion but what I would consider good evidence about the effects of voting on a national level; the rest has been defending it against someone waving it all aside, saying they don’t want any evidence except the axioms they select. A number of us are already quite done with evidence-free dismissals.
In that context just jumping in and casually skipping everything that was given and said, without bothering about backing up your contrary assertions, isn’t just voicing another opinion; it’s shoving over everyone above who provided evidence or argued for its importance. I expect it was inadvertent disregard, but now you’re caught up and know why it came off so badly.