Why are these players not considered strong list builders who've managed to build powerful armies with relative points efficiency? Why are the considered amateur dicks with no creativity or generalsmanship?
It's a balance exploitation issue. So many armies cannot answer 3 Heldrakes that it makes the game less enjoyable. It forces everyone else bar Tau into 'Forge World, Allies, or go fuck yourself!' situations (Dark Angels, Chaos Daemons and Chaos Space Marines are all 6th edition Codices that have essentially no native anti-flyer, let alone any 5th edition Codices). Bringing 2 Heldrakes and a unit of Spawn is still pretty brutal (probably as brutal as 3 Heldrakes if you play it right), but people don't frown on it so much as most people can bring an answer to it or create a new tactic to deal with it instead of just having to buy more stuff.
Flyers tend to make the game into an arms race - I don't really like the Stormraven model, or it's idea, and I didn't really fancy taking up a valuable Allied slot to take one. But I didn't really have much choice - it was the best, most effective thing to bring in a meta in which everyone else had a Flyer (I also converted a Mortis Dreadnought, which looks silly but I keep it since it's absolutely pivotal to protect my sorry ass from Heldrakes when I play DA).
3 Heldrakes is not actually that overpowered. Well, ok, yeah, against 90% of armies, it is. But an army with 9 Hydras or 6 Broadsides with attached characters to give them Skyfire and double FOC to give them 2 Aegis Lines with Quad-Guns will just laugh in your face. People don't like unbalanced lists - I probably gave a guy way too hard a time at an event I attended for bringing possible the shittiest list I've ever seen. It works both ways - people hate it when you bring an imbalanced list with 3 of the toughest, most powerful flyers in the game, people hate it when you bring 180 Boyz with 2 Big Meks, people hate it when you bring Footdar.
Is it because it seems some how easier to win with those armies?
It is. 3 Heldrakes is more powerful than any other combination of Fast Attack slots. You roll dice for them to enter play, then you point them at stuff you want to die. Stuff duly dies.
If you brought 3 squads of Long Fangs people tended to assume you were a win-at-all-costs jerk
You weren't? You were honestly bringing 3 units of Long Fangs for fluff reasons, or aesthetic? No, you were doing it to win. That's not a problem in itself, but you have to admit that if you're bringing 3 Heldrakes or 6 Night Scythes or 3x6 Long Fangs, you're trying to win at all costs.
Not sure what I'm trying to say here, because while I see where you're coming from, I would personally not enjoy a game against someone bringing 3 Heldrakes.