The point being that if you have a question and it is not urgent, you could ask by text and I will answer on my time. If it is something complex that merits a conversation, say so and we'll schedule a call when it is convenient for the both of us. If you cold call to inquire something complex and I have something more urgent or important to tend to, you are effectively stealing my entire attention. There's a reason we have asynchronous communication channels.

EDIT: This also applies at work, specially at work. I'm being paid to fulfill a set of tasks and achieve a specific goal. Not to suck up the ego of some random colleague who is being paid just as little as me. Unless my job is to literally answer calls at a call center, don't ask to ask, don't ask to call, just ask your fucking question and if it takes a conversation I will be the first one to suggest a time for a call. But don't cold call unless it is an emergency.