PENKO, I don't think I agree. In many airlines it's an established principle that in poor weather the pilots conduct a monitored approach or autoland. Certainly in my airline, in both cases the Captain is the PM until minima. This gives the more experienced and ultimately responsibile pilot the luxury of an overall perspective on the unfolding scenario.
Furthermore, in high pressure stages of flight it is quite common for pilots to suffer tunnel vision. If the pilot battling the wind and rain is also the Captain, what chance has the FO of comprehending impending doom and, more importantly, alerting the Captain and ensuring a safe outcome?
But you're right in so far as any Captain who feels that he or she is personally incapable of completing a safe landing should be diverting rather than shirking responsibility and delogating the task to a colleague. Nevertheless, where a Captain is confident that either they or the FO could complete the safe landing, that's when handing over controls is reasonable.
I will usually choose to be PM on sectors to new destinations or where conditions are such that I will need to retain overall spatial awareness and coordinate the flight with ATC rather than concentrate on the flight path. However, where a landing is likely to be tricky and I either don't know or don't have complete faith in the FO, for the sake of the aircraft's safety, and because I will carry ultimate responsibility anyhow, I will take the controls at the outset or for the approach.
But there have to be occasions when inexperienced pilots are allowed to gain experience in tricky conditions and it's the Captain's judgment call on when this takes place. If you don't do this you may end with a situation where new Captains are flying approaches in bad weather for the first time when the person in the other seat is fresh from training and represents a fairly frail safety net.
Who knows the dynamics of that Transavia cockpit?