I went to the site and you're right, they call it a "gland." I've been the neurosciences for 45 years and never before have I seen the hypothalamus referred to as a gland. While it does have neurons with processes that extend into the hypophysis (pituitary gland), neurosecretion (and neurotransmission via neurotransmitters) is generally not considered to be "glandular." And, the rest (and the bulk of this 4 gram structure) of the hypothalamus is devoted to electro-chemical neurotransmission.
And from WebMD: "The hypothalamus is a region of the brain that regulates sleep cycles, body temperature, pituitary gland."