It sounds like people are upset that 1. iRobot has time cards at all, and that 2. by giving us the option of a half-day Friday they are somehow taking advantage of employees.
1. Time cards: many companies have them. Not an excuse, just a fact. I don't like time cards, but I like my job at iRobot, so I'll put up with time cards. It's a low-overhead-slightly-annoying part of my week which is far outweighed by the parts of my job I love, which is most of them. If you really hate time cards that's fine - I understand and don't blame you - iRobot is not for you.
2. Half-day: The half-day is optional, so if you want to leave early on a Friday you work a bit more during the week and you're out early. Don't like it? Don't do it. I love it because I'm happy to trade a bit more work Monday - Thursday for an early trip to the beach on Friday. I work about 40 hours every week and consider the Friday "half-days" a good deal.
(Also, some people work from home on that Friday half-day, which solves the commute problem .)