"So Fitbit has designed a product to be worn by people who exercise... which does bad things when combined with *sweat*?"
They do recommend you remove it whilst showering, and to allow the skin to breath. I'm not quite sure why people expect to be able to wear anything 24/7 with no ill-effects. The Force did genuinely cause an allergic reaction, but wearing any band 24/7 will leave you with some sort of friction/contact sore regardless of how much it cost, much like bed sores from lying in one place constantly.
I have the next one down (Charge HR), and did develop a small red mark where the Heart Rate sensor presses against the skin, but that was only after I'd worn it a week (including to sleep), only removing it for showers. I just had a couple of days off, only putting it on when I actually went for a run. You're not exactly losing out on a whole lot of data if you take it off for a few hours whilst you're sat at your desk.