whether PL Buddhism is legitimate or not, it's still not a part of Theravada.
I think there tend to be two dangers in this kind of discussion: one is to overlook the common ground, and the other is to gloss over the differences.
Pure Land is relatively little-known in the West and thus is subject to stereotyping based on shallow knowledge about the tradition and its contexts. People are sometimes therefore surprised that aspects of Pure Land practice can be traced back to early Buddhism.
But at the same time, it is steeped in later doctrines such as Trikaya (Amitabha is considered sambhogakaya, Sakyamuni is nirmanakaya), the veneration of multiple Buddhas teaching sentient beings in the ten directions, the concept of Buddha lands, the notion of "upaya" (skillful means) and so on. More generally Mahayana views the Buddha as transcendental rather than historical. One line of scholarship traces this tendency back to the Mahasamghikas who are said to have emphasized more mystical and devotional passages found in the scriptures. So some of the tensions reflected in this discussion may go back a long way.
Now, perhaps, in a spirit of ecumenism and interfaith cooperation, we might play around with the idea that recollection of, say, Jesus is okay, because reason X (blah blah New Age syncretism or whatever). After all, if we're going to fit Amitabha in there, Jesus can come too, Laozi can tag along, it's all good.
With respect, I think this is off the mark. As heterodox as Pure Land may appear from a Theravada point of view, it is certainly a Buddhist tradition in the sense that it adheres to foundational Buddhist teachings -- samsara, the aspiration for a way out of samsara, the possibility of enlightenment. The "nuts and bolts" of Buddhism that are found across traditions are found in Pure Land as well. Karma and rebirth are very heavily emphasized in Chinese Pure Land, at least. Wordly dharma are seen to to be impermanent and saturated with dukkha. Nirvana is the ultimate goal for Pure Land practitioners, as it is for Buddhists in all traditions. Good sila is certainly important in the Chinese Pure Land schools.
So it's not correct to say that acknowledging Pure Land as Buddhist opens the door to considering Jesus, Mohammed, Laozi or the cast of Saturday Night Live as dharma teachers. That's a "slippery slope" argument and as such is inherently fallacious.
pilgrim wrote:If PL Buddhism is legitimate, there is no reason for any of us to be Theravadins.
Actually I would say that from a Pure Land perspective Theravada is for those who have the capability.