Obviously the question of heckler's intent is not a one-size-fits-all proposition. There can be many subtle reasons why someone may feel the impulse to heckle, including intoxication, sheer stupidity , and yes, even the desire to be helpful. I have come to believe that the majority genuinely believe they are making things better. I'm certain that the person performing on stage VERY rarely receives it as a helpful gesture.

LET ME KNOW WHAT YOU THINK: https://www.youtube.com/channel/UClDVs8bo49lsKIZUqg2d1oA/community

Lets look at the definition:
Heckling is the act of interrupting a speaker or performer with loud, rude, or annoying comments or questions. The purpose of heckling is usually to annoy or hinder the speaker. For example, you might say "Several protesters were heckling the speaker at the rally". 

Synonyms of heckling include taunting, teasing, mocking, ridiculing, baiting, bothering, riding, hassling, needling, annoying, hazing, jeering, and torturing. 

From the definition above, it's hard to imagine that some engaging in heckling believes they are being helpful. The definition fails to take into account the perception of "loud, rude, or annoying comments or questions." In the mind of many hecklers, they are none of those things. Many think they are improving the show. Self-awareness is lost.

From the performers perspective, the very act of trying to help says you think the performer NEEDS your help. We would rather you just leave if you're not enjoying the event. We consider every unsolicited interaction an obstacle and detour from our goal.

Note: I said unsolicited interaction. The proliferation of "crowd word", and the addition of interactive elemebts in broadcasting ofter solicit interaction, and that's where the waters begin to muddy. Inviting audience interaction tells the audience their voice is wanted and needed. There lines of acceptible vs non-acceptible interaction can be blurred.