Why top selling websites doesn’t have ‘add to cart’ on their main page?

Hi, new e-commerce entrepreneur here.

If you look at top selling websites (AliExpress, Amazon, iHerb) you will not find 'add to cart' button on a main page. I don't know why. The only answer I have found is at this article.

It says:

I recommend you not to put "add to cart" button in the product list if:

• your products are filled with details and usually are bought after thorough characteristics research. Better make them go to the product page to buy;
• people usually buy one item, not ten (unique products, expensive products);
• you are a fashion clothes shop

I feel not quite answer to my question. I mean your client have to make additional clicks if they want to buy something. They must to go to a product page and then make an additional action. Does it worth it?

I'm confused because the main goal of each e-commerce website is to eliminate a friction of buying goods on a website.

Here is my website I ask for argumentative critique. Thank you.