A lot of people are paying for their data. If a web page uses 40 mb and you have 4GB of data quota per month, you can only load 100 pages per month. Apparently the article text describes the page actually using 500 MB over 5 minutes, which means a 4GB quota can be used for less than an hour of reading.
Maybe it's different if advertisers or publishers are paying viewer's data costs. But some amount of restraint might be nice. Personally, I don't use a lot on my phone when I'm out and about, other than chat apps, hn, text NPR and lite CNN, cause I used to be on a plan with a hard cutoff. But then, I have unmetered networking at home.
I mean, the utility that matters is the utility for PC Gamer of showing everyone the ads vs some people refusing to read them over data concerns.
You might be paying for data, but you're not paying PC Gamer for reading them, so your opinion only starts to matter when you quit reading them over how much data they use.