Humans are social beings. We depend on each other; not everything we need to do can be done by ourselves. We do not produce every food we eat every day, and the same applies to practically every other aspects of our lives.
We often hear flat-Earthers ask if we have researched by ourselves all the things we claim. If we have not researched it by ourselves but only rely on information from third-party, then —according to them— we should not accept the information. It is merely their way to undermine society, and disconnect us from the rest of society.
We do not produce every food we eat every day. The same goes for science. A lot of research topics require mutual trust and cooperation among multiple parties, across several generations. Even for people who dedicate the majority of their lives researching, there will not be enough time to research every topic imaginable in their entire lifetime.
It does not mean the results of scientific research are taken as granted and cannot be questioned. We call something a scientific consensus precisely because it has been verified by multiple independent parties, sometimes over several years, or even centuries. Everyone is welcome to do independent verification. This is necessary & part of the process. However, just because we have not done the verification on our own, it does not mean we cannot accept the results.
Science is a social process. We stand on the shoulders of giants. Unlike other species, we have intelligence. We can continue the research done by our predecessor without doing it all over again. Humans cannot accomplish much if we as an individual have to rediscover everything again every time we are born into this world.
The M.O. of these unscrupulous flat-Earthers is to disconnect us from society and undermine our social functions. If they are successful, the victims will react to any unfavorable information with undue skepticism and reject them. Quite obviously, this only applies to ‘outsiders.’ They will have no problem with any information they never verified themselves, as long as it supports flat Earth.