There were family members who I found out later were offended that we didn't send out formal invitations and therefore they chose not to come, but it was truly our intention to ensure people did not feel any obligation to be there or send a gift. I felt bad that people were offended.
I think what you decided to do was the right thing. Some would probably act like they were 'offended' no matter you decided. Sometimes family dynamics can be challenging and/or some act like they always want to be in charge.
Relatives of ours were invited to a destinaion wedding of some friends to be held in Mexico. They didn't feel safe traveling there and it sounded like many others felt the same way. If you hold a wedding in a destination location that involves signficant travel, there is likely the chance that some won't be able to attend for any number of reasons. Travel, hotels, meals, etc. can involve quit a bit of expense for an entire family in additon to the cost of a wedding gift.
While the couple is certainly welcome to decide where they want to have their wedding, having it in a distant destination (international or not) will likely mean that some choose not to attend. Factor such as the cost and the overall logistics of travel might make it impractical for some to attend.