Only thing I can add to all the other reasons already mentioned is the most obvious one that gitlab has received a lot of press and exposure during the last 2 y

Only thing I can add to all the other reasons already mentioned is the most obvious one that gitlab has received a lot of press and exposure during the last 2 years and this in turn has made the number of eyes on the code grow. As with any software project; there will be bugs. As with any open source project; there will be eyes on the code.