In order to progress as a writer you need feedback, right? Many readers will offer advice and criticism, some better than others. You'll hear time and time again to "ignore the bad advice" and focus on the good. I, on the other hand, believe it's necessary to look at both good and bad advice. Yes, even if the person is trolling. Why? Because it gets you to think about your story in a way you probably have never thought of it before. 

There are plenty of people who mean well with their advice but the author will simply dismiss it without a second thought because they don't like it. Why don't you like it? Is it because this issue is resolved later in the story? It will change the narrative of your story entirely? It just doesn't make sense or is poorly researched? All of the above are fair reasons to reject advice. HOWEVER, you should always take the time to consider it, to see things from another person's perspective. You might notice flaws in your story you never realized were there. Of course, you never have to take this advice; it's just to make you think.

And hey, it also prevents your ego from surging. Plenty of times readers like to boost their favorite author's ego until said author believes themself to be above other aspiring authors. With this mindset, one can never truly grow. 

P.S. "Your writing sucks" isn't advice. It's a statement. And if someone says this without any example to back them up, then it's likely a factually wrong statement. You can safely ignore :)