PR stuff.
Federer is very honest and hardly hides his true feelings. Nadal OTOH pretends a lot on court and pressers. Fake guy. Still since Laver cup started they've been acting nicely to look as good friends - but that's purely for sake of money. I don't think Federer considers NADAL his friend. He is guy of really high self esteem (arrogant) -
he doesn't like someone who can challenge him on court, let alone liking someone challenging his standing in history books. He does not hate Nadal though (true in case of NOVAK).