I mean, what do you mean that they are apologising? Are they apologising because they drew something offensive or in poor taste? Or they have some insecurity about their skill or similar?
I'll start with me/ I have apologized for when my long hiatus began because I felt bad that I wasn't keeping up to the schedule I made. People were pretty understanding. I suppose in that case of comments that go "I miss this" or "Where you been" a small response such as : "Sorry, x has been going on and my schedule is inconsistent"
That makes sense. But there's no need to go on and on and on about how this and that are happening in your life and that's why you can't make updates. There's no need to make a bunch of excuses, just a simple announcement. However, I do think it's in our best interest to still have a solid schedule. For yourself and for your readers so they know when it's coming.
I made announcements when I was on a long hiatus to remind people that I wasn't going to abandon my comic. Though my readership is nowhere near what it was before, I'm consistent now. That's all that matters.
My advice: Commit to a schedule. If things come up, let readers know. There's no need for some longwinded apology like a celebrity getting caught saying a racial slur. Just a simple announcement and maybe responding to some comments that you are reworking your schedule.
Constantly apologising and continuing to miss updates indicates that you (any creator) need to change your schedule. Something is wrong, then fix it.
If you're talking about saying something that offends people, that's a different story