So what if a security researcher is paid for their work? We don't say Lawyers are not Lawyers because their being paid and not doing work pro bono.
Remember security research takes lot's of time, skill and hardware they should be paid to do their work.
There is plenty of room between blackmail and research. A professional researcher can draw a paycheck and release exploits as found.
Exactly how are these "professional researchers" generating their paychecks?
(NB: I was one of those "professional researchers".)
Agreeing on money up front seems like a reasonable way, I also see no problem with bounty programs or even asking for more from bounty programs. Withholding a bug until a bounty is raised is were I would draw the line at blackmail.