For me infinite-scroll is one of the most stupid features of the "modern" web. It just makes the experience worse to crank up some dubious engagement numbers.
And to make it clear: I don't want to search for stuff via $string site:reddit.com via some search engine. Often I really want to search for exact $string on a page, but on something like Reddit that does not work anymore.
[/rant]
EDIT: Thanks for all the answers. And I think I hit a nerve here :) Maybe it makes some frontend developers take a step back and really think if it's really a good idea to implement that "feature".
As suggested you can use old.reddit.com in case of Reddit, but for some pages, there just isn't an option and the worst offenders even hijack your CTRL-F and want you to use their own terrible search.