It says unauthorized streams... but what does that actually mean? In my country they are broadcast free-to-air. Do you need to pay to watch the games in some countries?
Someone paid for those free-to-air broadcasts. They reclaim the money from advertisement. For example, in Germany, ARD and ZDF paid €152M for the rights to air the 2026 World Cup. To answer your question: any stream from non-ARD/non-ZDF source, or a source not directly sub-licensing the stream from those two, is an unauthorized stream.
You can't just put it up on the internet because it "came free". Putting a German stream for viewers not physically in Germany would be even worse.
Absolutely. In Canada one of the big media companies had exclusive rights to broadcast the games. They do offer OTA broadcast if you have a digital antenna, although I don't know if everything game was available there. Otherwise it was a $30/month subscription to TSN+ or I believe they had a discount to get access for the e entirety of the world cup for $50-$70 (can't quite remember).