I’d say it’s more of a generational thing. Even Disney animated films like Frozen are rated PG by today’s standards. And keep in mind that back in 1980 ESB was rated PG. People are just more sensitive about things like this nowadays.
EDIT: Also the Han/Kylo scene towards the end* might have tipped the rating over to PG-13. Add to that some of the things mentioned earlier, the rating isn’t what I’d call unreasonable. Tad prudish, but no entirely without merit.
*(are we allowed to do TFA spoilers at this point?)