In fairness to your ignorant friend, but many “designers” stick to tools like Figma and XD and do not really get into the coding side of things. Fundamentally, the web is based on HTML, CSS and JS if you want to be a developer then you’ll be up to your neck in it or server-side language generating some combination of it. If your goal is to be a designer, that is a different set of skills and doesn’t necessary require those technologies