Capitane I can understand your frustration. It can be disconcerting for an uploader to suddenly switch file hosts. However, you have to also look at the situation from the point-of-view of Sanet and the uploaders.
One of the main reasons that Sanet is arguably the biggest English language warez site on the web is that it attracts a huge amount of uploaders. The uploaders are well aware that RG and NF are the two most popular file hosts on the web, so they probably have no problem using one of those services. However, they may well have had a negative experience with one of the file hosts. Maybe they feel that the host was underpaying them, deleting their posts too soon, etc. The point is that if Sanet demands that all uploaders upload to a file host that they don't want to use, they will probably just not post here any longer. In the long run, that's not good for Sanet, the uploaders or the community.
Of course the ideal solution for a user is to subscribe to both RG and NF, as this would give you almost 100% coverage of all Sanet posts. Understandably, many users are not willing or able to subscribe to both hosts. In that case I recommend a Nitroflare subscription. It's cheaper than RG, and almost all uploaders here use Nitroflare. However, you really can't go wrong subscribing to either host. These are the file hosts of choice around the web, so your money will not be wasted if a uploader here suddenly changes to another host.