Well Moreindor, that's because there's already tons of youtube videos setting up xp farms in outposts, making them usefull to get credits and some other few achievs.

That's how I did it too. In a planet with 1local hour equals to 92 UT iirc, with iron and aluminium in it. 8hours slpeening could grant me enought to craft frames and jump 2 lvls, with the romance boost on.

For me, Organics feels like a chore in comparison.
But I see your point. Something must be pushing players from this achiev.

The most annoying (time consuming) achievement for me is to level up to 100. Harvesting organic resources was relatively easy. I just jumped the wall on Jemison (New Atlantis), ran all over the place and harvested every single plant I came across. It took about 2-ish hours max. Easy-peasy.

But the (legit) grind to level 100 is something else. I'm not into crafting or outposts so I've been trying to level up via gameplay, quests, combat.
I spent many hours on Schroedinger and Hawking (both have abundant fauna, Hawking is level 75) decimating the local fauna.

I've only made it to level 83 so far. It's incredibly grindy and boring and progress has slowed to a crawl because the higher your level, the less XP you get.
Life Begets Life was a complete cakewalk by comparison and I don't get why less people have this achievement than the level 100 achievement.