Well... The Google tells me that "grease monkey" is a derogatory term for a mechanic. I don't think it is generally meant to describe someone that you think very highly of. The Google also tells me that "craftsman" is a person who is skilled in a particular craft or art. I think this is generally used as defined. The Google never lies.
Using the two together seems to imply we have "skilled people who care about elegant code and tool selection" and "mechanics that like to tinker". Like I said, I don't think that is how you meant it... but that is how it comes off to me. And I tried really hard not to project any value judgement.
The point of the analogy is to suppose that the primary goal of the PHP developer, as with a supposed typical repair mechanic, is to dive into the work and do what needs to be done to get to having a working site (or whatever project). I believe this is similar to the sentiment expressed by the adage "Real developers ship."
The "craftsman" approach in the analogy is presumed to be more deliberate in his work, placing more emphasis on ensuring that the highest quality work is assured, and comparatively less on the practical matter of ensuring that it delivers what is needed on a short turnaround. One aspect of this analogy that may be relevant to consider is that craftsmen are considered to produce high-quality furniture and other products, but those products are quite expensive compared to the products made in factories that most people (can afford to) buy.
In professional development, software developers are generally expected to balance these concerns. Produce the highest-quality product that it is practical to deliver within a reasonable time frame.
No doubt this analogy is still an oversimplification of what PHP developers (and other developers) are like, as virtually all analogies tend to be. But it isn't intended to be derogatory toward PHP developers -- or toward developers in general whose focus is on shipping a product and not producing the perfect architecture.
I guess in order to buy into the analogy you first must accept the premise that being a craftsman and using PHP are mutually exclusive. I do not accept this premise. But maybe we can just agree to disagree on that.
That's part of what I meant by calling it an oversimplification: all of any developer pool are not going to fit some description.
Does the analogy apply to enough of the PHP developer pool to have value? My guess would be yes, but if your experience dictates otherwise, I have no problem with that assertion.
Using the two together seems to imply we have "skilled people who care about elegant code and tool selection" and "mechanics that like to tinker". Like I said, I don't think that is how you meant it... but that is how it comes off to me. And I tried really hard not to project any value judgement.