There needs to be an aerial challenge for it to count as an aerial duel according to the official stats. If there is no challenge, it is most often counted as a clearance. This is the same for everybody.
These are just the official stats. Someone used the same stats to claim he was among the best in the air in the entire PL however I think that’s the wrong conclusion.
I 100% agree there are more important things for a modern CB than being good in the air.
These are the official aerial stats. You are probably right that a post that includes those stats is negative.
The stats I showed are the official stats from Premier League and from whoscored.
Fbref have another definition for aerials won and all players have higher stats. According to fbref he has won 1.67 aerials per game in the PL, however that is very low figures compared to all CBs, as it puts him in the 8% percentile of CBs in Europe top leagues in terms of aerials won.
https://www.premierleague.com/players/67191/Lisandro-Martínez/stats