I reckon it's ok to get some ideas what others are using as keywords, but just copying them is not really fair. I think you can improve your English vocubular even more when looking the words up in a dictionary.
Nikon D700 with Nikkor's, Nikon 90x, Leica X2, Canon S100
I agree with you it is copying. But, common, it is not illegal.
Lets say I have the same keyword as another photo, the potential buyer will find both pictures. At the end he is the only one that will choose to buy or not.
In addition I must admit that I use a web dictionary www.reverso.net that give me many words
5 – Quickly read and check/correct what you have just copied
Some users just copy keywords of similar images BUT DON'T check them. For example: I tag all my photos with my user name "jdanne". Surprisingly searching for "jdanne" will find more photos than the size of my portfolio. It's so easy to check keywords with an online dictionary but obviously some members are too lazy to do it.
Dreamstime does not allow such practice and you should not recommend other users to do this. It is true that you can check the image info of other images and use as model in case you do not know how to keyword but copying word for word is not allowed. This usually results in spam.