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Creative Commons made an ideological decision to make Commercial licenses the default

Of course they did. They also made an ideological decision in creating the licenses in the first place. This connotation of "ideological" with "bad" is obnoxious.

they promote them as "Free Cultural Works" to make them sound more appealing.

Yeah, just like people say "free speech" even though you often have to pay to get your speech across.

Or maybe it's not about money at all.

But I'm sure you were just unaware of that. It's not like HN talks about it every other month.

For CC BY, CC BY-SA, and CC BY-ND, Creative Commons itself explicitly mentions the word "commercial" in its summaries: https://creativecommons.org/licenses/

Of course, if your description is correct, Yahoo/Flickr may have an interest in downplaying that important detail.

But it's only commercial in the sense that it permits commercial use, but it also explicitly leave the creator out of any compensation beyond attribution.