This is something that I, as a Hindu, believe. God is fully present everywhere at all time. If this is true, then how can we argue that God is fully present everywhere but cannot be fully present within a manifest form? What then are the objections against the possibility of a personal form of God?
I reread this several times, and focussed a bit on "within a manifest form." Fully present within is not same as fully present
as a manifest form. I think it gets tricky and I would say delusional. If we accept form as "the reality," I think it is delusional. And yet, I freely admit that I have acted as if physical is real, and 'other' is the delusion.
I do think another way to understand this is via night dreams. Outside the dream, I understand the illusion for what (I think) it is. I understand that my mind is manifesting the form as myself, a physical self. And that, I am really all beings within the manifested reality that is the dream world. Yet, within the dream world, that is not my awareness. Instead, I am quite convinced that form is real, that my perspective is limited to my solitary physical self. i am further convinced that the other participants in the dream are not of my making. Even upon waking, I may utter something like, "hey friend, you were in my dream last night."
I understand God Self as fully aware of (God) presence within the perceptual order of forms. That God is not the dreamer, nor limiting (self) knowledge to perspective of I am (as) form.
So, the objections, as I see it against personal form of God is that God Self will not portray Him (or Her) Self as, "I too am that which is (your) illusion." Or, I too am one who is isolated to this form. Instead, I do think God is highly personal in sense of being fully present within all manifested forms. In human understanding and desire to quantify, I find this to be beyond (my) comprehension. I feel it is known to me, while limited by my choice of self awareness (as a being stuck in solitary form).
Hope this helps. The other responses on this thread I think say similar message. The 2nd post, by Marble, says it far more concisely than I just put it.