In Chrome you don't even need to open the developer console. To get a comma separated list, just go to:
https://www.reddit.com/subreddits
Then paste this in the address bar:
javascript:$('body').replaceWith('<body>'+$('.subscription-box').find('li').find('a.title').map((_, d) => $(d).text()).get().join("\",\"")+'</body>');javascript.void()
The trick is that when you first paste it, the leading "javascript:" gets stripped off. So you have to type it in again.
This will give a list in the browser:
javascript:$('body').replaceWith('<body>'+$('.subscription-box').find('li').find('a.title').map((_, d) => $(d).text()).get().join("<br>")+'</body>');javascript.void()
He talks out of both sides of his mouth. On the one hand the third party apps are costing them a lot of money. On the other hand, he says that only 3% of users use third party apps. Is that 3% of users the only thing keep them from being profitable?