I think what parent is saying is that camera-captured interlaced video was displaying scanlines from different images in each field, whereas game consoles using

I think what parent is saying is that camera-captured interlaced video was displaying scanlines from different images in each field, whereas game consoles using interlacing displayed the even/odd lines of the same image in two fields. Thus parent's argument is that we can consider camera-captured interlaced video to be 60 (or 50 for PAL) fps despite being interlaced, but games using interlacing were 30 fps. It makes sense to me.