Vendor lock-in, and buying IP from companies who had much better records. People in open source have been pissed at Oracle since they pissed on OpenSolaris and started suing everybody who uses Java after buying Sun.

Oracle is famous for having a corporate philosophy of "make lots of money, nothing else matters".

Larry Ellison is famous for being a selfish megalomaniac: he owns an island on which hawaiian natives labor for him as serfs, and he has made two donations to charity in his whole life: one in exchange for dropping charges in a security fraud scandal, and one to establish an anti-senescence research institute for his own use.

Don't take a job at Oracle, don't buy their products when possible, they are the back alley mobsters of silicon valley.