Ok guys listen up, I had approximately 1.3k plus photos that needed to be deleted. Here's how I managed to do it under 15 mins albeit it still took abit of hard work and lil bit of time. But first:
Preface.
My guess when they made this iCloud thing, they didn't want people to have an easy way to inventorize and quickly delete the photos / vids cos to upsell iCloud paid packages (insert Apple has changed remark here). So my guess when I discovered this loop a disgruntled employee got fed up of this too so he/she wrote this small hack in.
The Problem.
Once logged into iCloud, we all know you've gotta choose the photos one by one, or you could choose multiple photos by holding 'command' key BUT if you're not good with the mouse and you accidentally click the white space in between, it's game over. You gotta start again. It's the worse feeling ever cos you've been so diligent and one mistake you gotta start egain. Basically it *****. Then I noticed on one of the threads if you go to 'Moments' you press the '+' button, it'll choose all the photos from that day. So that helps a bit if you took a lot of photos that day.
The Solution.
Here's where the hack comes in. I noticed when I chose a day that I took a lot of photos and pressed the delete button, it'd delete as expected, BUT ALSO pre select the following photos to the amount of last deleted minus 2. So for example: I chose a day that had 35 photos, clicked the deleted button, once deleted, click the delete button again and it'd say delete: 33 photos. Then click yes. It'll keep on going down to zero. Everytime, minus 2.
So then I thought, okay how bout I'll pick another busy day, click '+' button and keep on clicking photos but super duper carefully. So I managed to make it to 109 clicked photos. Then press delete and repeat the way my process. I figured at this rate it'd just take a few cycles and I'll be able to finish it. Woo hoo. UNFORTUNATELY, it only works at a max of 69. So the next round of delete it said 'confirm delete 69 photos' as opposed to the 'confirm delete 107 photos' I was hoping for. Nonetheless it was still alright, the cycle was the same 67 then 65 etc.
Anyway, I hope this helps. Peace from Malaysia!