Ahh, hopefully it gets a fix soon, as it can be demoralising to some players who gauge their learning by the points. 
Yes! It’s annoying too.
Im not sure if the admins will do much about it since the global leaderboard was taken away as it doesnt really effect anyone directly therefore they think it needs nothing to do with them. Yes it is annoying to see that people are exploiting for points but not much will come from it
Just my two cents… dont shout at me if you dont agree but it is probably the truth as this is a minor issue compared to other things e.g. Bugs. i can invite an Admin into this topic but to be fair they probably wont do much if anything
ML
This is a bug from Memrise. Each learning gives you 200.000 - 500,000 points. This only happens under IOS (11 - 12 developer/beta).
Nobody needs the global leaderboard. You can also delete the points easily.