I'm not sure what your referring too?
How are you unsure that your opinion was an opinion?
The "voting for the lesser of 2 evils" isn't just saying there are more than 2 parties to vote for. It says the 2 major parties are evil and implies the other choice aren't. You can certainly have the opinion that you're right and the lesson is that there are more than 2 parties to vote for, but it's an opinion.
In my opinion, the phrase is nonsense, and all politicians GOP, Dem. Green and Libertarian are considered evils by other people.
So not sure why you don't understand that your opinion has no more merit than mine.