Why are transactions older than 3 years have no or incorrect timestamps? For example, when looking at the genesis block on nanolooker, most of the transaction timestamps are unknown and nanocrawler has most of them set to Jan 1, 1970. I know they used to exist at one point because of old videos like this one. So are the block explorers currently bugged or were timestamps intentionally removed?

The reason why I feel this is important because of incidents like the bitgral hack where having timestamps is very important for transparency of the network. The article mentions a reddit user pointing out that while the bitgrail exchange had closed all withdraws, there were still withdraws happening during the closed period of 17-19 Jan. Try looking at that address now to find transactions during that period. You can't because all the timestamps are gone...