I don't think an attractive person should be conscious of other people's feelings just because they're attractive. While I can understand the sentiment and insecurities of someone less good-looking, life is not fair.
If you want him, tell him. Don't be a little bitch. If he doesn't want you, move on.
Average looks + confidence > Good looks + low self-esteem.
Having said that, Sugawara is having her own god complex moment, deciding to play with Kazusa's feelings just because she's hot and above other people. The right thing to do would not be to fuel Kazusa's jealousy, nor to encourage her low esteem, but to smack her out of her own head, and tell her to get it together. Mulling about things you can't change surely won't change anything.
My point stands that Sugawara (or any other hot person) is not responsible for everyone's feelings, and is not at fault if Izumi actually liked her (which is unlikely).