I don't think modesty has anything to do with it. If you like white shoes, buy them, wear them and just ignore the fashion police if they begin to harrass you!
My cycling shoes are mostly black (Sidi and Lake road shoes, SixSixOne mountain bike shoes), but I do have some red Shimano's (SPD), some bright blue Shimano's (SPD-R) and some black/silver Garneau's (with Crank Bros. eggbeater cleats).
So buy, wear, ride what you like . . . modesty isn't an issue.
Rick / OCRR