We see alot of people holding on the the coins they invest in, either they are afraid to loose out on future gains, or waiting for a rainy day when they can cash out, does this not effect the market with so many coins not being traded, causing the fluctuated trade movements, with people mass selling when the market starts to fluctuate?
I don't see the reason why holding would have any negative effect on the market price for one, when people hold, its a way to control the market because for a popular coin, it means the demand would be more than the supply which would force the price to increase, the percentage that is being held is not always enough compared to the percentage in circulation to have distort the market.
However, it comes at it's own risk too because the coin you are holding with the mindset of increasing might end up being permanently worthless.
The market is so diluted at this time that anyone is free to pursue any interest he feels its most beneficial to him without stopping others from pursuing theirs. So, if holding is achieving your interest, its all good if otherwise, pursue something else.