If we're talking self promotion on someone else's feed or posts, then yeah it's bad,I'd even go as far as saying they should be banned just for the 1st offence alone. I instantly block that s**t if I see it happening on my channel or other social media posts, no warnings, nothing, just delete and block.
If we're talking about asking for subscribers in your own video (or your other social media posts), then you have absolutely every right to & should be [mind you, I never got into the habit of asking & still forget most of the time, a very unfortunate bad habit to have]. People who say to let something grow naturally when it comes to something business related, have generally never worked a day in their lives in a growing business. (Although maybe they already work for 1 that's so successful & big it'***** a plateau, you can never really tell with entitled & illogical idiots).
It's like being a salesman/saleswoman, a key piece of advice management usually pass on in the guides that people usually never read, is that you have every right to ask for the sale. A good salesman/saleswoman will rarely let a customer leave empty handed. If a customer is struggling to decide on something & you don't ask or press, it'll go nowhere. Trying to sell a laptop, you offered the customer a discount & they hit you with the "I'll think about it and get back to you." Or some bull like that (sometimes it's a getaway, sometimes they genuinely want time to think). So the best course of action; you print out of brochure or spec sheet, put your name on it or write up a quote for them with the discount (they don't leave empty handed) & ask them to come back to YOU. This way if they do come back, the sale is yours (doesn't go to your colleagues... most of the time) or you can even call them a few days later for a follow up and sometimes you come across a customer who actually forgot or didn't actually think about it until you brought it up again & decides there and then to come back to buy it.
It isn't all that different when it comes to your own videos & channel. You're sort of selling a service, despite the $0 upfront cost, people still need to invest time into your content but people forget. They don't come onto YouTube with the mindset of hunting for content creators (usually) they come on to switch off & wind down. Not everyone is avoiding that subscribe button on purpose. Believe it or not some people might actually be enjoying your videos that they don't realise they should or could subscribe. Asking for subscribers is a good reminder, either mid way or near the end of your video. Although I'm usually against asking at the start of a video, there's a very good reason why it's done and that's because it sticks with people, whether they like it or not (you remember when they ask, especially if you don't like it). I have loss count of the times I've watched a video, enjoyed it, then Youtube's recommendations keep suggesting that channel's videos & maybe 5-10 videos later I'm like "Wait, if I'm gonna keep watching their content so I should probably subscribe." It actually happened recently-ish with Quite Shallow, exactly like that actually & this happened over the course of a few days to a week.
