I don't think that it is manipulation, but it was sure that when things will get sold against Monero, it will see a dump for sure...
But you cannot decline the fact that XMR is more secure against Bitcoins, because it has that inbuilt mixer for which you need to pay in case you need complete anonymity for bitcoins and so it also possesses the potential to rise back again, even more than where it used to be...
Of course it is manipulation, that was already proved by the market (XMR is down by like 40% since the creation of the thread). This is one of the main problems, which cryptocurrencies have. Some of us (me included) are trying to prove that cryptocurrencies are money, but you can't explain that to the average Joe, when we have such volatile market. When he invest his 5$ into Monero (or Bitcoin if you wish) and one week later he sees that he has $2.5 in his account, then you already lost him as a potential user.
Yes, many people are making money in that way, but this is not doing any good for the masses. If some of you are fine by that, I'm not, but everyone is entitled to his opinion...
I wouldn't call it necessarily "manipulation". This is the behaviour of pure "greater fool" speculation: buying at price X with the hope of finding an imbecile who will buy at price 2X (because he thinks he'll find an ever greater imbecile that will buy at 4X who thinks he'll find ...). When the belief in 2X stagnates, obviously demand plummets, and the price with it.
But, as you say, this is the big sadness I'm also having about crypto: instead of having a market cap mainly sustained by usage (by the demand to *use* the bloody thing), we have market caps that are mainly sustained by "greater fool" demand. That is always extremely volatile. In fact, that demand cannot exist with a stable price and a stable price expectation: there is no hope for a greater fool, and there is no fear (nor of uncertainty and doubt, nor of missing out). While a stable price is needed for usage.
Of course, when usage increases, price would rise too, that follows from Fisher's formula. But it would be a solid price increase, sustained by more demand for its *usage*, and hence essentially independent of the beliefs of future price variation (which would be more of an unavoidable nuisance of increased popularity than anything else).
but tactics are bad. As usual polo has insiders on this too.