Momentum trading isn’t about price discovery. It’s about front running whales. And that is negative to the real economy: whether it be bear raids or it be creating instability in commodity prices or taking money from people who are buying for cashflow and value (and not for price).
I think you are trying to create a moral component to trading when there isn’t one. You can easily say: who cares if I contribute. I’m having fun, earning and not hurting anyone directly. You will be amazed at how many people say that on a bank trading floor.
I agree with a lot of what you say. Regarding certain topics I'd argue differently.
Broadly speeking I don't think there is a way not to trade/invest. We do it whether we want to or not. If you take all you money and put it under your bed then that's a trading/investing decision, too. Doing that for years your money will have lost a huge amount of value due to inflation. The decision catches up with you whether you want to or not.
I get what are you are saying. Certain parts of the finance industry seem and probably are more useful than others. Let's stick with that criterion of "usefulness" in the economic sense and leave the morality aside.
The long term investor and the venture capitalist provide risk capital which is needed for new ventures and innovations.
So what does the speculator do?
I would say there is a certain standard or benchmark and that is investing in the broad market via ETFs according to neoclassic economic theory.
And then there is us! Retail traiders as well as hedge funds who are able to use way more tools than a classic retirement account (leverage, short selling, derivatives) with the explicit goal of either making more gains than the market or making the amount with a lower volatility.
This is creative destruction in Schumpeters sense: https://en.wikipedia.org/wiki/Creative_destruction
You are trading momentum, correct? In the last 20 years scientific articles about factors like "momentum" exploded. It is way different than theory and practice of investing in the market portfolio.
Who is right? Only time will tell!
What am I trying to say?: The better approach will prevail and become the new "best practice".
Being a speculator means actively taking part in the hunt for improvement and it even means being at the forefront like an entrepreneur with a new invention. The vast majority of entrereneurs and inventions fail but the ones that survive can contribute hugely to the prosperity of a society.
p.s. "A world of chance" by Brenner and Brown describes beautifully how speculators and gamblers were historically quity essential and paved the way for certain important developments.