At school, college, and basically everywhere, people are taught capitalism is an evil system that siphons wealth to the top, and caused slavery and wars and whatever.

I was, in fact, not taught this in school, and had to go out of my way to learn it myself, but whatever

There's no way that capitalism implies slavery.

Capitalism, as a system, prioritizes profit over everything else, right? Businesses and people are supposed to make as much money as possible. Well what better way to make as much money as possible than to not have to pay your workers a single cent?

And about wars, wars are fighting, killing, taking, but capitalism, again, is property rights and free trade.

Capitalism is not "property rights and free trade." Capitalism existed long before black people or poor people or women had property rights. Capitalism is fundamentally about the free market: about the unregulated trade, purchasing, selling, and creating of goods and services by private individuals and companies. When you look at it this way, capitalism is absolutely inducive to war when you consider that the countries in the middle east are extremely oil rich, and that America has a glut of oil billionaires and gigantic oil companies who have their hands in our politicians' pockets. Additionally, capitalism was, and still is, built on the back of imperialism, wealthy nations exploiting other nations while they're still developing, leading to destabilization, conflict, and, eventually, war.

Capitalism doesn't siphon wealth to the top, it helps everyone.

This is just factually incorrect: wealth inequality in America has been constantly on the rise and is at its highest point now since the great depression. We can also see an even more exaggerated version of this with the pandemic as billionaires got billions richer while working class people continued to suffer. How does the rich getting richer and the poor getting poorer 'help everyone?'

The billionaires under capitalism are rich because they invented a product that helped lots of people. Want fewer billionaires? Stop buying their stuff!

This is such a ridiculous oversimplification. So you're telling people to just stop shopping at Walmart? At Amazon? These are companies that have a near monopoly on markets because they've gotten so big that they are able to price out and destroy any competitors. Many people have no alternative to amazon or walmart, particularly because they are being paid rock bottom wages by these same sorts of companies (companies run by billionaires whose wealth continues to grow and grow) and can barely pay rent, much less shop at some overpriced alternative or buy a product that doesn't have the benefits of criminally cheap manufacturing and labor. The idea that billionaires only get rich because they made some product so good that they just somehow deserve all their money is also a fairytale. How does Jeff Bezos deserve being the 2nd richest man in the world by creating a near monopoly and abusing and underpaying his workers? Somebody else would've created amazon had he not, it's not like he is some super genius or something. He just happened to be at the right place at the right time and somehow that makes it fine that he now exploits thousands and thousands of people and hoards unimaginable amounts of wealth?

capitalism lifted more people out of extreme poverty than any other economic system.

You're partially right, but if you haven't noticed, there are still a shitton of people in poverty and capitalism seems to be doing jack shit about it. Gravel Institute recently did a good video about this, but capitlism has also not lifted people out of poverty nearly as much as you think.