Well they say

*As high as 2.2 °C, with average downwind air temperatures 0.7–0.9 °C warmer than corresponding upwind areas. Thermal signatures were detectable at distances up to 500 m"

"As high as", combined with "up to" show two upper limits, but you can be sure if they were simultaneous they would have said so, especially when considering their prhasing of downwind being warmer comes after mentioning the upper limit. It really seems like you are supposed to overlook that it's an upper limit and subconsciously add another 0.7-0.9 on top.

What they are saying is you can feel the warm breeze coming off the hot thing if you stand near enough.

A comparison to other industrial sites would put it in perspective. As would a distinction between localised warming which is what is happening here compared to global warming where small temperature differences at a global scale are far more significant. The publicity about global warming risk has put a lot of effort attuning people to the significance of those small temperature shifts, to co-opt that education to make people fear a situation where it doesn't apply is undermining their work. That puts us at more risk than any one data centre. People can observe a local increase of 2 degrees in relative comfort and think that it won't be catastrophic at a global scLe.