Why do they even like Hinata so much.. like seriously. She's not even a main character. Not bashing, but seriously.. I don't find anything interesting about her besides the fact that she's just a character. They treat Sakura, the heroine, like kitten and Hinata, the background character like a freaking Goddess.

MY POINT EXACTLY.

They treat her like a goddess because they think she's moe and put her on s pedestal and kiss the ground shew walks on
Actually, her position is very reasonable. Her confession was the climax of her character development so it's not surprising to see her above Sakura. Had the character popularity poll been taken before her confession, I'd say her position would be below.
only cause of all that "OH NARUTO AND HINATA WOULD LOOK CUTE TOGETHER!!!!" logic
Yeah, it's a fluke, happened in part 1 with the poll that was done shortly after the time of the HinataxNeiji Chunin exams fight too. Whenever any character has more of a focus in an arc around the time of a poll their numbers go up, except for Naruto and Sakura who stay pretty consistent over all- especially Sakura who is almost always the top female character, Naruto fluctuates between around 1-3 and he's the title character. Sasuke out polled him in a few and/or Kakashi in a few. In the Japanese Jump polls Sakura has been the top female character, except for the two polls done right around the time where Hinata got a significant story moment, and even in those two Sakura was right behind Hinata in the rankings. I think due to cultural differences Sakura is consistently less popular than Hinata in the west. (plus the fact in the west more people watch the anime than read the manga, where in Japan millions read the manga where only thousands watch the anime... and we know how the anime distorts the storyline and characterization...) Interestingly, for some reason Temari is more popular in the west than in Japan (but it seems to be from what I've seen of the ShikaTem shippers online not due to any accurate character portrayal either from the manga or anime. The fanart portrays her as much more passive than the character is in either the manga or anime and this off-characterization seems to be liked by a lot of naruhina shippers. I don't know where this passive Temari portrayal comes from as even in the anime it's rather obvious she's a tsundere type, even more brash than Sakura, in fact, brash and sarcastic at that....
YUP, cultural differences. More to the point that Sakura isn't LADYLIKE like how westerners view women. As you pointed out ciardha Tsunderes are never well accepted in the west because they portray the EXACT opposite of what girls are viewed as. People say Girls are supposed to be nice, and reserved, and let males "dominate them" like Hinata.