I assume they are pulling from Crunchbase, but it's not like people have any incentive to keep Crunchbase updated (in a lot of cases, you don't want people to know you just raised $1.5mm a year or two after your initial seed money).
To channel Biggie Smalls via Ben Horowitz, "don't you know Bad Boys move in silence and violence?". If competitors don't know you're well funded, they're more likely to ignore you. On a more practical level, it keeps the bottom feeder companies which troll crunchbase/techcrunch/etc and spam you with recruiting/etc. offers for months away. There's not a lot of upside in letting people know you're funded before a product is launched.
