Who are the prominent feminists that you're talking about? I can't think of a single one that has said that confidence is a negative trait, in men or women. Quite the reverse, actually: people who are secure in themselves do not need to demonize others to support their self-worth. That goes for other genders, other religions, and other political views. If a woman turns you down for a date and you're self-confident, you shrug your shoulders and pick someone else: it's the men who are not self-confident who are likely to call her a "dyke" or a "frigid bitch".
Every political movement has its radical nutjobs who get a lot of press because they're radical nutjobs. Judging feminism by the nutjobs is like judging all Republicans by Glenn Beck, or all Christians by the Westboro Baptist Church.
I have been dating a politically active feminist for over twenty-five years now, and I count a number of self-identified feminists (some academics) among my friends and family for longer than that. Some are lesbian, some are bi, but most self-identify as straight and have successful, self-confident husbands. I imagine that all of them would roll their eyes at the phrase "feminist agenda" or a "gay agenda". Those aren't real things. They're just scare words.