I can't give you any numbers to support or refute your suspicions. However, if you genuinely believe that there is a need for something like Bitcoin, honest individuals using Bitcoin will help legitimize the currency and hopefully drive down the level of fraud and other unsavoury behaviour. If that is your only objection to it, then presumably honest folk like yourself staying away from Bitcoin are also preventing it from becoming more acceptable (not that you have any duty or obligation to do otherwise).

Or, are you implying that there is something fundamentally immoral about Bitcoin itself, which cannot be affected by having more honest users? I admit that this could also be the case, for example, if Bitcoin turns out to be such a massive success that it destroys the ability of nations to collect taxes, affect monetary policy, etc.

I do understand that illegal activities being paid with Bitcoins is something that comes with the benefits of the system. You are correct, the ratio of legal/illegal activity will probably improve with time as more legitimate business will be conducted with Bitcoins. At the same time it's worth being concious of the fact that at the moment the biggest use of this tool is paying for criminal activities. If this is true, we can't pretend that bringing in more "real" money to the pool doesn't mostly aid criminals.

What I see as "fundamentally immoral" about Bitcoin is the fact how so much of it has been acquired by black hats through bot-net and hacking of exchanges. They OWN a fixed percentage of this economy thus their net worth increases every time fresh "real" money is brought in anywhere in the pool. There is no way around it that I can see.

To give an analogy, I would personally not eat in a restaurant if I knew it is co-owned by local drug dealers even if the food was delicious.

Obviously I can see the positive side of having the ability to process payments without going through the government. This discussion is not black and white for me at all.