Some marriages end in divorce because of the 'incompatibility' of their partner with their in-laws. It is easier to give in and have respect for your partner's parents, than to cause stress in the family.
If you have problems with your in-laws, it's best to be direct and have a positive conversation with them and work towards resolving the issue like grown adults.
Your partner should also be present to be the 'catalyst' that calms everyone down.