Stop worrying about whether articles are written by LLM or not and judge them by their content or provenance to sources that you can justifiably trust. If you weren't doing that before LLMs then you were getting fooled by humans writing incompetent or deceptive articles too. People have good reasons for using LLMs to write for them. If they wrote it themselves, it might cause you to judge them as being a teenager, uneducated, foreign, or whatever other unreliable proxies you use for trust.

You point about Valve's response is valid though.