Why do people snore? Does it point to any disease?

Throat vibration. Snoring is the vibration of soft tissue in the throat. The possible disease is obstructive sleep apnea. Obesity with thick neck circumference is most common, though recessed or lax mandible or tonsils can cause. Can be nasal due to adenoids or deviated septum. Diag osa with sleep study. Osa can lead to poor sleep, pulmonary HTN and heart failure if untreated with CPAP or surgery.
Narrowed airway. Snoring happens as muscles relax during sleep and air flows through a floppier smaller airway . If snoring is chronic it may be a sign of sleep apnea (osa) that is associated with daytime sleepiness cardiovascular disease , diabetes and headaches for example.
Perchance to snore. Many have innocent snoring when they are extremely tired or have drank a great deal. If it occurs while on one's back, changing position works. Although less frequent, the snoring can be nasal. Humidification, decongestants, nasal strips, or nasal septal repair can assist. If not, a nocturnal oximetry that measures oxygen levels throughout the night can signal need for a full sleep lab evaluation.