If OpenBazaar has listings including drugs / weapons etc on there then I won't be using the platform and I know of many other legit retailers who would follow the same principle.
Its going to be further complicated by individual country laws ie. UK You can sell either seeds or hydroponic equipment but you can't sell seeds and hydroponic equipment together because we have laws covering incitement. It is illegal to germinate a cannabis seed in the UK so listing a propagation light or advising a customer on growing techniques along with your seeds is covered by encouragement laws. It is not even necessary for there to be evidence of a crime being committed to secure a conviction for the incitement part.
If the items you list are legal in your home country and in the country you ship to then I see no problem. It could get messy very quickly though.
This is why I'm unsure of how well it is actually going to work. I think there should be different versions of open bazaar and maybe they will. People really aren't going to be wanting to be listing 'legit' items on a site where you can buy drugs or the worst type of porn. There should be specific sites for each thing. For those that want to buy drugs they should go to the decentralized market on the darknet and for those who want to buy candles or alpaca socks they go to another on the clearnet. Regardless I'm sure it's only a matter of time before a decentralized deepweb market pops up (of there isn't one already - though I haven't heard of it).
Same as BitcoinAccepted here, im not going to be using anything ilegal. I don't want my coins to be mixed with coins that have illicit origin. Thats the problem of a public ledger, if you get some coins that are proved of illicit origin it may be a problem for you. Who would accept them as payment?
Well since BTC is not refundable it shouldn't be a problem, but it still hurts its fungible features.
A lot of dollar bills are used in crimes or are the subject of crime. But they still spend just fine.