So if everyone searched "is google down" and visited the link on downdetector that was returned in the search, that would add to the downdetector count for that site.
Downdetector doesn't actually know if the site is up or down.
Downdetector only reports an issue if a significant number of users are impacted. To that end, Downdetector calculates a baseline volume of typical problem reports for each service monitored, based on the average number of reports for that given time of day over the last year. Downdetector’s incident detection system compares the current number of problem reports to this baseline and only reports an issue if the current volume significantly exceeds the typical volume of reports.
https://www.speedtest.net/insights/blog/how-downdetector-wor...
Probably reported Google as “down” because a whole bunch of people use the word “Google” when they mean “internet”.