As others have said, you shouldn't let how other people feel affect your character choice. Choose who you'll have fun playing and feel good for winning with. Don't let hate scare you from a character but at the same time, don't feel obligated to play one out of some personal loyalty (though having a personal connection with a character can help). And as Wintermelon said, I think people only dislike/bash Jigglypuff herself. I don't think anyone will hate YOU for playing her. If anything, being able to win with her will get you respect.
That said, when it comes to an objective choice between
and
, you're probably better off with Kirby. At launch, the two were probably about even in terms of competitive ability, but as the meta has developed, I feel Kirby has really climbed ahead. Jigglypuff does have good air speed, a better air game, likely better recovery, being harder to combo, an easier time dealing with zoning, and clutch move in Rest which does have some setups. But Kirby has good tilt frame data, greater weight, a fast fall that makes landing easier, vertical recovery, more range, better ground speed and ground game, nice throw combos, generally better specials with Inhale being able to completely change matchups when landed, a versatile combo starter and grab confirm in D-Air, is actually getting patched, has a better matchup spread, and (most important IMO) a solid killing option and answer to shields in his Up Throw. Jigglypuff does have stuff that distinguishes her from Kirby, but I think all of Kirby's advantages overall make him a more solid choice. That said, you shouldn't feel forced to drop Jigglypuff. As I said, play who you like. But if we're talking objectively here, Kirby is the superior choice in my eyes.