LOL, what a bad troll you are.
I think he/she is just unfamiliar with Bitcoin, and is guilty of transcribing arguments from other scenarios.
To bemoan the deflationary nature of Bitcoin due to 'killing investment' is an inappropriate piece of transcription.
A traditional argument against a deflationary currency is that investment will be hindered due to reluctance to spend money which will be worth more in future.
For the argument that investment may stall to make any sense, Bitcoin would have to be so widespread that most of an economy's capital was tied up in it so that little other investment capital was available. (or so insanely deflationary that no investment other than bitcoin was attractive)
If the majority of the capital is still in other currencies, then from an investment perspective Bitcoin can also be considered just another asset like gold or property.
In the case where bitcoin is the dominant currency; the extent to which bitcoin is deflating would indeed act to subtract from the rate of return on investments.
I submit that Bitcoin's deflation rate will rise if the economy is vibrant (requiring more bitcoin transactions) - thus putting the brakes on borrowing and investment, but the Bitcoin deflation rate will lower if the economy slows - making investments more attractive.
This is of course an experiment that hasn't been run with a highly divisible currency with a fixed issuance rate - but it doesn't seem helpful to have someone simultaneously arguing bitcoin will be 'dead in 3 months' whilst criticizing it for some flaw that they perceive in an alternate universe where Bitcoin has taken over the world.