Should IGN have better due diligence? Sure, but it's a company run by humans, and humans make mistakes. Hell journalists writing for news outlets about damming stuff that can have fundamental impacts to geopolitics also make mistakes, let alone writers giving subjective opinions about fucking video games. Point is, mistakes happen, and it's stupid to hold their feet to the fire as if they'd done something far more contentious or evil.
How are they a problem to the industry? They are by far the most popular video game outlet, and that by in large means a tremendous number of people enjoy their content, formatting, design etc. Simply put you don't become that popular, or even sustain that popularity unless you offer quality content that people enjoy or want.
And your second point is just beyond immature lol. Who even cares about due dillegence, other people's honest mistakes justify our own. Right? He did it I can do it. Eye for an eye and all that.
I believe the OP has asked for the mods to correct the thread anyway, so like the IGN review titbit, that too will likely be corrected.