Were two black men legally removed from a Philadelphia Starbucks?
Maybe - its complicated.
The crime of trespass in Pennsylvania relevantly involves:
3503 (b) Defiant trespasser.--
(1) A person commits an offense if, knowing that he is not licensed or privileged to do so, he enters or remains in any place as to which notice against trespass is given by:
(i) actual communication to the actor;
At face value, the store manager asked them to leave and by refusing to do so they committed the crime. However:
(c) Defenses.--It is a defense to prosecution under this section that:
(2) the premises were at the time open to members of the public and the actor complied with all lawful conditions imposed on access to or remaining in the premises; or
If the condition imposed was "buy something or get out" then that would be a lawful condition and trespass would have been committed. If the condition was "because you're black" then that would be an unlawful condition and trespass would not have been committed.
Now, the evil and insidious thing about unlawful discrimination is that there are lots of perfectly lawful masquerades that it can wear. Indeed, except in egregious cases, the unlawful discrimination can only be inferred by a holistic look at a large number of interactions to see where any particular one falls on the scale.
That said, this particular case feels like racial discrimination.
With respect to Starbucks, if they could show evidence that it routinely asks people of all ethnicities who did not make a purchase to leave then this would not be racial discrimination - just bad business practice. However, given the particular business model of providing a place to rest along with an opportunity to buy sub-standard coffee it seems unlikely that this was the case (I'm Australian so I completely fail to understand why Americans insist on drinking bad coffee).
With respect to the police, this is a little less clear. It is not their job to determine how a court (or DA) might decide a case: its their job to determine if they have probable cause to believe a crime is or has been committed. They have a store manager who has asked people to leave and people who are refusing to do so - probable cause for trespass. That said, police have discretion as to how to handle the situation: they could talk to the manager, they could ask the patrons to leave or they could arrest them. They can use their discretion however they like: unless it is based on unlawful discrimination. Which brings us back to the beginning.