Why am I downvoted so heavily? I tested the website in two computers and have payed my attention to any element in dev console, then wrote down all the issues I have found. If I was rude or something, why not just to tell me?
When I was younger, I thought it was enough that I was speaking the truth, even if I phrased things harshly. I'd think to myself "they should listen to what I have to say, because I'm correct. If they don't like how I phrased it, that's their problem." Unfortunately, humans aren't robots. If you're going to deliver harsh feedback, it's important to do it in a way where the other person is likely to accept the message you're trying to communicate. Otherwise, you may as well have not sent any message at all.