Gambling, porn and drugs are not shady unless abused, like anything else. There is nothing morally wrong with doing any of them, however they are categorized as "sinful" from a religious perspective which has made its way into law. They are considered illegal or crimes in many places, to which there is no victim.
If you look at it from the wider perspective of society as well as the beliefs of those who occupy positions of power and make the laws, then that is a minority opinion. Whether we like it or not, most people still believe that those things are wrong even if most members on these forums (including me) might not subscribe to that belief. If Bitcoin wants to become mainstream rather than being merely confined to libertarian circles then from a marketing point of view at least, I think it makes sense to de-emphasize those aspects.
It's interesting to see that you mention Just-Dice and Canadian gambling laws. What's funny is that the we have lottery and gaming corporations in Canada run by the government. They are even able to market and encourage lottery and gaming to the mainstream through TV commercials, radio, internet ads, etc.
We have state-sanctioned lottery games here too. Usually the revenue generated from those go to schools and community projects. As I said, gambling is probably the least controversial out of the so-called "sinful" activities that I listed.
There is nothing morally wrong though, as it brings harm to no one. So whether or not these things are taboo or against what certain people stand for, doesn't mean anything to anyone else. It's a belief system that needs to be subscribed to.
Porn/prostitution with consenting adults has no victim. Gambling has no victim. Drugs has no victim. You can argue that people that abuse these things can harm themselves, but you can harm yourself with anything done outside of moderation.
So to say that gambling is wrong, but if the government owns the corporation, then everything is fine and it's not wrong anymore, is exposing an incredibly stupid mindset. If someone thinks its wrong, then simply don't do it. But to take freedom away from everyone else that doesn't share that same thought, doesn't make any sense.
A vegan thinks it's wrong to eat meat/dairy, so should eating meat be illegal for people that don't share that belief? As stupid as it sounds, it's as legit an argument as gambling/porn/drugs, or maybe even more so as animals are being killed.
Anyways, back to bitcoin, to start restricting its use based on what the transaction is for doesn't make sense to me. Pre-bitcoin all shady transactions were done in FIAT, and it's likely still a significant majority that's done in FIAT, and it doesn't give FIAT a bad name.
I do think that there is some rationale for the banning of certain hard drugs which have a much greater potential for harm vs. soft drugs like marijuana or even LSD but other than that, you are pretty much preaching to the choir. Not once did I say that I personally believe any of those mentioned activities to be morally wrong.
Bitcoin sees very little economic activity compared with fiat. Fiat is used to buy your baked beans at the supermarket. Fiat is used to pay the mortgage for your house. Fiat is used to pay for your children's college educations. Bitcoin isn't. Until recently, the vast majority of the Bitcoin economy was comprised of "underground" elements and this association was only beginning to be shed from the beginning of last year. Fiat, on the other hand, has much more varied set of uses and the "underground" elements only comprise a minority of the fiat economy. Since this association has hurt mainstream adoption of Bitcoin in the past and is something that the Bitcoin community is trying to distance itself from, is it really wise to be actively encouraging underground markets to adopt BTC at this point in its evolution?
I'm not a vegan myself but if I lived in a society where 95% were vegans who opposed meat/dairy consumption, I would not like to see Bitcoin being targeted towards livestock and poultry farms, slaughterhouses, and butcheries - especially if the (presumably) taboo meat/dairy industry already comprises a significant share of the Bitcoin economy.
Society is irrational and illogical, but if Bitcoin wants to be mainstream then unfortunately, it must pander to society's views and expectations.