It's not bad having plastic shopping bags, but I think people who throw them out are bad.
Plastic shopping bags themselves aren't bad, rather people who fail to recycle these bags are bad.
ーIt's not bad having plastic shopping bags, but I think people who throw them out are bad.
「プラスティック製の買い物袋を持つのが悪いのではなくて、それらを捨てる人が悪いんだと思う。」
plastic shopping bag(s) で「プラスティック製の買い物袋」
throw out で「捨てる」
ーPlastic shopping bags themselves aren't bad, rather people who fail to recycle these bags are bad.
「プラスティック製の買い物袋自体が悪いのではなくて、むしろこれらの袋をリサイクルしない人たちが悪い。」
rather で「むしろ」
fail to ... で「…し損なう」
recycle で「リサイクルする」
ご参考まで!