Trading algo generating revenue in a bull market is a meme among many trading communities.

No, bull market or bear market- this is why it is a trading Algo. You have to make sure you make a reasonable profit in both directions.

It seems you never built an intelligent one!

But that's exactly my point?

Most algo's, especially ones made as a 'side project', are actually just directional bets and not true algorithms. And there are cheaper ways to take directional bets thus most of these are actually losing money - if the author just understood their directional bet, they could buy relevant stock/options to have the same risk profile for cheaper. But compiling algorithms back down into their directional components is an entire field in quant finance, akin to something like DS&A for CS.

Which is the joke I was referencing. When you take a directional bet and win, that isn't proof you're algorithm 'worked', it proves your directional bet won. Akin to someone who "vibe codes a website" and then sends you a localhost url. It's proof you're just making shit up and not aware of what it is you're building or how it works.

I see your points. The difference is that I do not intervene nor I select the strategy. The algo can decide if it buys/close position on stocks , bonds, stock options. Depending on the macro economy and situation, strategy adapt (again with no human intervention ). Also the algo analyzes every night several thousands stocks from European , Asian and US markets.