While I'd personally rather have more users over here producing comments and posts and such, I'd point out that unless something has changed, you can browse Reddit without an account or logging in, from a Web browser. You just can't post, comment or vote.
Specifically for subreddits flagged as NSFW, Reddit's "new" Web UI will demand that mobile users install their app, but you can bypass that by using the "old" Web UI.
goes to check to see if that still works
Huh. Actually, there is a change, but not the way I'd expected. It looks like at least where I am, California, now even the new Reddit Web UI lets anonymous users into NSFW subreddits using a mobile web browser, just by clicking on an "I declare that I am 18+" button. That definitely had not been the case. Maybe these countries declaring age restriction laws basically made them review their policy, and some of the changes have actually made it more-permissive, based on geolocation of IP.
e.g.
https://old.reddit.com/r/nsfwcyoa
Now both are accessible. I will bet that that's not what people in the UK see, though (well, not unless they're on some sort of VPN with an exit node in a place with different laws).