It’s also very important for Ferrari’s marketing cachet if Schumacher’s seven championship haul remains unmatched, after all they provided him with the machinery to win five of those WDCs and will forever be associated with him. There’s some corporate pride at stake here, hence Vettel’s comments.
It’s also worth noting that Vettel is quite strident in his support for Hamilton’s political activities, even taking a knee in support.
Would be a great shame to see a driver like Perez bounced into a Sauber in deference to Stroll, he deserves far better but then so did Esteban Ocon when he was turfed out.