I dont know about halal but Many Religions laws and doctrines was written thousands of years ago and those laws may not have illustration with trading online as we do now, but religion is practice now as a fanatism hub and even if there are no illustration, religion scholars who is against the trading will find away to Bend those law in Favour of what the like and don't like.
I don't bring religion into my business, once my business don't require cheating on someone, harming someone, or endangering someone's life.
Pretty much you've exhausted the topic. 100% agree.
1- no one wrote down rules about trading thousands of years ago
2 - even if there are now some people (eg priests) who think otherwise, these are only their interpretations
but..
trading may cause behavior and arouse emotions that are described as sins (such as greed). If you trade based on your strategy, trying to put emotions far away ... there is nothing bad about it. You just add liquidity to market.