I think it depends on the team. Some teams are simply better for a rookie to start at than others, and it's not always correlated to the speed of the team.
I believe Ferrari's instincts are correct - for itself. It is the most pressured team in F1, from a media standpoint, so any driver going there must be rock-solid. A rookie by definition cannot prove this, even if their junior record is perfect. The Ferrari team have all seen unprepared drivers get crushed by that expectation, not only in F1, but even with some of their development drivers in GP2! They also know that their development scheme is relatively low in structure, and that the level of guidance in their F1 team for a rookie is low even by F1 standards. They've never had an incentive to engage in rookie hand-holding, so they have never developed that side of it. At that point, caution in employing rookies is understandable. Most importantly, they have the ability to simply select the right people for them, most of the time.
McLaren were a great team to start at in the Ron Dennis era because of the in-team communication method worked very well for some and the team being very good at providing disciplined support. However, they were only a great team for a specific kind of driver. If you didn't need the support (e.g. Montoya, Senna, Prost) it was awful, and if you had a different style of communication to McLaren (e.g. Kovalainen, Perez), it wasn't any good either. Alonso failed on both counts. Of course, some of the people I've used as examples weren't rookies at the time, but the principle would have been equally applicable to them had McLaren been thinking of getting them straight from junior formulae.
Red Bull is not such a good environment, and to me Toro Rosso doesn't solve the problem. This is because it is the opposite to the old McLaren system - constantly moving goalposts, command-and-control leadership, little reliable support once arriving into F1. If it was possible to start elsewhere and still go to either Red Bull team later, that would be the best thing.
(Note: Vettel did precisely that, because he raced for BMW - if only for one race - prior to starting at Toro Rosso. So did Ricciardo, with Hispania. They're Red Bull's two greatest home-grown successes. I don't think that's a coincidence, because BMW provided that little bit of extra disciplined support he needed at the time, and he just needed to carry that structure to Red Bull/Toro Rosso).
Mercedes probably could take a driver straight from F2 and help them well... ...but why bother, when there are so many of its development drivers being used as pawns to help secure customer teams' loyalty and do rival teams favours (to be banked in paddock politicking later)?
Of the other teams:
- Force India has historically shown itself to be a good place to train up as a rookie.
- Williams has also been a good place, but only for bold, stubborn self-starters (which is why I'm surprised Lance Stroll didn't stay splattered after his reputation fell from a great height while there - I hadn't taken him as being like that at all, but maybe he is and I didn't notice).
- Haas has a sample size of zero, so I'll reserve judgement.
- Renault won't be a good place for a rookie until it stabilises itself, which may take a couple of years.
- Sauber is an awful place for a rookie at the moment. It had better improve by next year.