Whatever may be the end goal, MITM is called an 'attack', not 'research'. I'd not last a single day at such a company who would ask me to do such things. I had worked for a national political party in IT and left the job once I found about it corrupt practices and scams. If we, as engineers collectively upheld ethics as part of work culture, Meta wouldn't have attempted it.
Just saying, it's really hard when your job or even your future green card is on the line. When the grunt engineers are 1 mistake away from being sent away from the US and lose all their potential futures in the US, they are much more likely to bury their heads carry out what they are told from the managers.
We need to go for the higher ups more.