I read some discussions that those old bitcoin movements can create fear on the market. People think those old bitcoins can be dumped on the market and will cause a price fall.
Why should people spending or moving their Bitcoins make you fear/panic, even if the owners decide to liquidate their funds, there is nothing you can do about it, if you pay attention to fud, you might also sell your coins because you think the worst is going to happen, but the funny part of it all is people who sell like this more often than not start to buy immediately when an appreciation starts, just because of the fear of missing out. I'd advice you not to pay too much attention when people move their coins, even if it hasn't moved for a long time and is worth so much, it is their coins.