@Needmoresleep
I knew other expats who barely set for outside the expat bubble. Not elitist, just people who were more comfortable with the known
They'd moved to a foreign country to live and work, it's safe to say they were comfortable with some unknown or they'd have stayed put 
I did not know that the proportion of French was so small
Yes, that's from LSE's official statistics. It's good to go off facts.
It was a bit of a throwaway comment.
Come now, that's not true. I recognised you telling that anecdote before. A search of the words "French", "LSE", "corridors" and your name shows you've told that anecdote at least four times over the past four years (more if you don't include the search term "corridors"
). That's not a throwaway comment, it's a pointed one.
(I'm assuming you didn't mean it was a throwaway comment from the students who told you, because surely someone as worldly as you wouldn't make assertions based on a student's throwaway comment.)
I’m not sure private school ever came into it.
Perhaps not for you, but with respect you must have gone to LSE over 30-40 years ago. I didn't go there, but I respect its expertise in statistics. Going by figures from LSE itself, in 2014:
The total number of undergrad offers it made to students from schools in the UK = 64%
The remaining 36% of undergrad offers would presumably have been made to international students (at non-UK schools).
Of that 64% of upgrade offers made to students from schools in the UK:
29% were made to students at private schools in the UK
39% were made to students at state schools in the UK
Source: www.whatdotheyknow.com/request/lse_2014_undergraduate_admission
That 29% v 39% percent is a telling statistic. Obviously not everyone who was made an offer would have accepted it, but it gives. credence to the perception by many that there are comparatively a lot of private school students at LSE. There would presumably have been so many more state applicants than private school ones, so if you were a private school DC applying for an undergrad place starting in 2014 you were in a rather nice position.
I appreciate and respect you want to promote and defend LSE as you and your son went there and it is of course a very acclaimed institution. But peddling personal emotive bias rather than facts isn't helpful to prospective students and their parents.