Sure, they can call it however they want. Technically they're the same language. There are only minor lexicographical differences, the grammar being roughly the same. Blame Stalin for the confusion.
Technically, they're different, which makes the question of whether they should have a different name a political one, not a linguistic one. As the saying goes, a language is a dialect with an army and a navy.
No, technically there is just Romanian language. The difference is purely ideological/political. If the U.S.S.R. have had more ambitious plans for Germans, there would have been more names out there for the same German language. Or for any other language for that matter.
The argument over Moldovan being a seperate language was promoted by Stalin, but the argument also predates Stalin by a century, so I am not sure he is to blame for this particular thing. Everything else, sure.