Some possibilities, definitions from Merriam-Webster:
imperceptive: not perceptive; lacking perception
obtuse: lacking acuity of sensibility or perceptions; having or showing neither delicate feelings nor alert awareness
oblivious: lacking active conscious knowledge or awareness; unnoticing, unaware
shallow: 3b: lacking in depth of knowledge, thought, or feeling
naïve 1: marked by simplicity, ingenuousness, or artlessness:
a: showing candor, freshness, and spontaneity unchecked by convention, social diffidence, or guile.
b: showing lack of worldly experience: innocent, simple.
c: unsuspecting, credulous, and unwary about duplicity or distortion
2: marked by lack of instruction, experience, perception, or learning:
a: exhibiting lack of analysis, subtlety, or depth by ready acceptance without consideration