Honestly I think a lot of people who have never made a gif for tumblr don't get that it does actually take time and effort, its not just rip it from a video and post it- you have to download the video, in my case I have a video player installed that grabs continuous caps, figure out what parts you need, you have to open those in photoshop or gimp, depending on where you got photoshop you might be paying for it every month and then on top of that is actually sizing, cropping, colouring, sharpening, adding text, etc. etc. like it is something that takes time and effort for which the only real reward is creating something that makes you happy and hopefully people reblog it with a nice or funny tag, so maybe keep that in mind the next time you think gif makers are being mean or unfair for being upset about reposts. It is its own little artform that is fairly unique to this website, and that's a big aspect of why I have always loved tumblr, if all the gifmakers stopped posting things would be a lot more boring around here.