TdF question about sprinter's points. potential spoiler

Why were the sprinters going for sprinter’s points in today’s stage when 10 riders finished ahead of them? I thought the first ones to the line got the points.

The points go 25 deep at the finish. When there are only 27 points separating the top 4 in the green jersey competition, every point counts.

Thanks. I didn’t know the points went so deep.