People who call Resident Evil 7 a return to the series' roots are usually speaking based on preferences, which is why it's a false claim. Resident Evil's roots are in all the elements from the original game that were passed on, expanded, and improved in its sequels. Anything changed or added is a deviation, or just simply an addition to the overall formula.
When people say first-person was a departure for the series it's a factual statement, regardless of personal preference. Las Plagas in RE4 for example, is a direction I didn't personally mind, but to say it's not a departure for the series would be false.
Resident Evil games have borrowed elements from the original game with varying results, and games like Resident Evil 4, Resident Evil 5, and Resident Evil 6 were called into question for deviating from the series' roots, and rightfully so. The same can be said for Resident Evil 7, because despite what that game gets "right" about the series, it does just as much "wrong."
But because people favor survival horror, they're going to boldly claim it's "Resident Evil" again, and cherry pick common elements, even though all games in the series share common elements, despite the varying degrees of evolution and deviation in those games. Resident Evil 7 isn't so much a return to the series' roots as it is what Resident Evil 4 was for the series, a transition to a new style of Resident Evil game.
