Everydody whines about RNG. They all remember unfortunate games of which their opponent queued a deck with no chance of winning just to chain together a string of events so unlikely and powerful in which they won. Everybody remembers when against all odds ragnaros hit face, or the mage topdecked fireball, or maybe when the doomguard discarded every card besides the other doomguard.
But this is the fun of the game. The presentation of hearthstone is so incredibly complemented by the joy of winning against all odds due to something you cannot call skill. Without RNG, hearthstone is just a shell of mechanics that pales in comparison to other card games better established and more diverse in playstyle and skill level than hearthstone.
I do not play hearthstone because it is competitive: i play it because it is fun. For me, the fun of a game never stems from competitiveness, my rank nor skill is of any importance. The absurdity of games, and the RNG making sure no game feels unwinnable from the begging nor eerily similar to the previous makes Hearthstone a fun game to boot up time and time again.
People will whine about MMR screwing them over, how they can never seem to get lucky, and how their rank is not a reflection of their skill. If your only pursuit is rank 1 legend, you will definitely have a worse time than the rest of us.