The conclusion of a master's thesis at Lund University / LTH (Sweden) onto that topic provides some information on why green is chosen over red:

When it comes to the performance of green light in comparison to red light, we have seen that under white smoke conditions, on average, green light has performed better than red. While under black smoke conditions, red light was the better of the two, in line with the previous research. Nonetheless, the reason why green is the most commonly used color still remains independent of its performance against red light. As previous literature has proven, people perceive green as safe and tend to choose it over red in these situations.

https://lup.lub.lu.se/student-papers/record/9084340/file/9089830.pdf