I don't think you appreciate how valuable firsts are in the NBA. 20 and 26 can get a lotto pick, so unless you also think lotto picks should be traded for just okay players, it doesn't make sense to criticize them like they're nothing. Second, how often do you think multiple firsts are actually traded? It's not that common, even for stars. George, Kawhi, Butler, Paul and Irving all went for one pick or no picks. The Mavs gave up multiple picks for Doncic and Porzingas, but the former was a trade-up in the draft and the latter was a much bigger gamble than people acknowledge.
Second, unless you think White and Murray are just blech players, it doesn't make sense to piss on the Spurs' ability to use those picks to get better than "known NBA quan ies". It's not an accident that the team gets "steals" every year. If they see the forward equivalents of Murray and White (say KZ Okpala and Brandon Clarke), I'd rather let them decide how badly they want to keep their picks.