there are bots who are able to check if a image is a repost or not and they can then remove the post if it’s a repost.

to my knowledge this limit existed already for a long time. it’s intented to prevent scraping and automatic bots. They basically want prevent people from using bots who act as a browser instead of using their API (where they can limit them) to do stuff on reddit.

They also have a automatic system detecting when too many clients access them with similar or “odd” characteristics (weird useragents, referers, amount of requests, weird headers in the request etc.) - if they detect such a case they usually limit you and then completly block you for hours, days or months. I couldn’t open reddit on my chrome app anymore because that as an example (i was developing an reddit client and they detected my useragent browser name as “too old”… so they just banned my browser while others worked fine )

i 99% of the time use old reddit so dunno about that. but usually if i get replys to old comments its actual users and not bots. sometimes i replied to them and asked and they said they found it random by looking through reddit and google as an example.

i sometimes get comments to sometimes even 6+ years old comments. it’s rare but happens and i always wonder how someone found my comment after this time.

why? because you don’t want to see certain things in your feed. people come hwre for various things. some people come here to mentally relax, so they don’t want to hear about negative topics like wars or people Fighting all the time. other people just are not interested in certain topics or posts but have them flood their feed.

example: i come here for relaxing mentally and to see posts about topics I’m interested in. so I don’t want to see negative stuff like causalities in wars, hearing people complain what bad things they experienced this day, what stuff has gone wrong in their life and other negative stuff. another example is lemmynsfw where I don’t want to see males showing their genitals to me since I’m interested in women, not guys. so i block communitys who are about such things.

short: because people don’t want ro see certain stuff. that’s why there is a block function. lemmy without a block function wouldn’t be useable since you get flooded with tons of posts you aren’t interested in by default without any blocks.