TechTakes

corbin's already nailed it. This is just another example of Nazi apologia, in which someone makes death threats that their supporters try to defend in public as just metaphors. I don't think it's essential to refute what the OP was saying, but here's my attempt:

But this is a deeply stupid story with a lede that basically says "I'm unfamiliar with even the most most famous 90s hip-hop". Tan, like many, many, many Internet commenters before him, was quoting Tupac's Hit 'Em Up, which, unless you think Tupac was literally calling out hits on Chino XL, was not intended to be a true threat at the time, and certainly couldn't reasonably be taken as one today.

Yeah, that's not how any of this works. As stated in the article,

The “die slow, motherfucker” line was a reference to a Tupac Shakur song, and Tan later apologized. That 1996 song, “Hit ‘Em Up,” escalated the simmering East Coast-West Coast rap rivalry into a lethal feud; Shakur was gunned down three months after its release.

So the OP is straight up wrong about being "unfamiliar with [...] 90s hip-hop," the research is right there. Also, I am not well versed in rap and rap culture, but I understand that in the 90s, rap and hip hop were intertwined with gangs and murder- thinking that a death threat in a song was not literal and "not intended to be a true threat at the time" is... naive at best, I imagine.

OP also says the threats "certainly couldn't reasonably be taken as one today." I don't think this is true. Let's look at the threats themselves:

[...] Fuck Mobb Deep! Fuck Biggie! / Fuck Bad Boy as a staff, record label, and as a motherfuckin' crew! / And if you wanna be down with Bad Boy, then fuck you too! / Chino XL, fuck you too! / All you motherfuckers, fuck you too! / (Take money, take money) / All of y'all motherfuckers, fuck you, die slow! / Motherfucker, my .44 make sho' all y'all kids don't grow! /

I don't think there's any other reading than the persona announcing their intent to use a ".44" on all the parties listed, which is a death threat for sure. Additionally, IANAL, but according to Greg Hill and Associates,

Death threats in a rap song can constitute criminal threats or threats against a crime victim (Penal Code § 140(a)) even if the victim never hears the song.

So yeah, I think this could still "reasonably be taken as [a threat] today".