Some grammar books refer to this use as present progressive with "emotional comment." It tells what happens regularly, but also gives the speaker's attitude about the sentence. (For that reason, you need to know the context to decide if it is appropriate or not.) The action happens regularly or all the time, but we use the present progressive (with always, constantly, continually, forever, etc.) to show how we feel about it. We approve, disapprove, like, dislike, etc. This makes it different from just stating a fact about what happens regularly in the simple present tense. My girlfriend is always cooking me special meals. (I'm so lucky to be in love with this wonderful woman.= I'm giving the idea that her doing that makes me happy, fell special, etc. ) My girlfriend always cooks me meals. (...because I don't get home from work until 8:00 p.m.= I'm just giving factual information.) Somewhere on this big internet there is a very good article about this topic, but I can't find it at the moment.

I don't agree that there's a blanket rule about continuous + always expressing annoyance. If you said, "He always does this" in an irritated tone of voice, it would sound just a annoyed as "He's always doing this." Likewise, "She's always helping people" sounds like you are talking about a good person, just as if you'd said, "She always helps people." Again, I think it is tone of voice (or, when writing, punctuation such as exclamation marks) that makes the difference, not the tense.