Lol, you cannot "encourage" yourself to do something. You do it or you don't. If "encouraging oneself" is outlawed, then "thinking" or "reaching a conclusion" is effectively outlawed as well. And that's completely ridiculous. I agree that this is an unfortunate way to end an election, but come on. A person can do to their vote whatever they please.
The point of the restriction on campaigning for invalidation is that people should not feel pressured by others to undermine their own democratic right. That's the sense I have gotten over the years.
If we're being perfectly honest though, my preference for freedom of speech actually makes me wonder if we should ban the practice of campaigning for invalidation in the first place. Either way though, spoiling your own ballot is a democratic right that is not prohibited by the letter of the law.
While Velasco's action may not have been illegal, I don't think it would be wise to set the precedent that invalidating one's own vote because of knowledge obtained after the vote was made is a "democratic right." At the very least, it makes the game more unrealistic given the impossibility of such an action irl.