That just depends on so many things, perhaps said people live an environment cooler than yours, or their PC has better cooling than yours does, or their graphics card is more high-end with a much more capable cooler, or they run a custom loop, or maybe they have replaced the thermal paste on their GPU with something better, and a billion other reasons that could cause a different person living somewhere else with a different system than yours to have a different GPU temp when playing the same game as you are at the same settings.
P.S: 75C is a perfectly fine GPU temp, anything below 85C, your GPU is happy to run at.