Thanks, Mesabe! And Maggie, wow! Jackpot!
I hope you'll forgive my speculation about this, but I'm wondering if the forest person you heard was truly pissed off. I ask because the timing of the sound was so interesting. Whoever sounded off waited until the family left, and only you could hear. You are one of the few (the only one?) in your family who is open-hearted about them, is that right? And they know that. So it might be that they were grabbing an opportunity, with the rest of the family gone, to communicate with you, and only you.
Most of the "conversations" I've had with the Tall Ones in the woods were very clearly straight-ahead attempts to connect in a loving way, but some have been confusing. The "growls", for example. I've been "growled" at twice. I was terrified the first time. I was completely unable to interpret the meaning of the sound I heard, so I stopped dead in my tracks and asked -- verbally, out loud -- if they could make a second, "confirmatory" noise, IF the noise was intended to stop my forward progress on the trail in the woods that I happened to be on at the time. I heard nothing. Complete silence. So I interpreted that to mean all was fine, and I went on my way, with no incident. (I know I say this all the time, but I strongly recommend this course of action whenever you hear something you're not sure how to interpret. Ask, ask, ask for more information. That says so much to them. It says you know they're there and who they are. It says you are a reasonable person, and not a hot-head; not a threat. It gives them a chance to clarify, if they feel clarification is needed. And if you hear continued noise that appears to be escalating in intensity, turn around and leave. Do not collect $200. Do not pass go. Just leave. If they're making noise, and you have the sense it's not a hello noise, then they just want you to leave, and you should give them that. They won't hurt you. If they wanted to hurt you, you would never hear them coming....)
Okay, sorry. So anyway, I got a second "growl" a week later, in the exact same spot, but this time, it was softer and closer: right at my elbow. The softness of that second sound clued me in, in a subconscious way, to the fact that the "growl" was in fact NOT a growl, but a kind of greeting, a hello. They were acknowledging that they understood I was scared the first time, and they were trying to "ratchet back" for me this second time, but they were determined to say hello, anyway.
I had one other kind of quasi-ambiguous vocalization when an invisible "squirrel" rushed AT me, chattering madly away. At the end of the quite recognizable, otherwise unremarkable "squirrel chatter", the chatter suddenly crescendoed into a scream of what sounded like rage and frustration, which scream then abruptly ceased. At this point, I was kind of acquainted with their antics, and I doubled over in a fit of laughter, but then immediately tried to regain my composure (I didn't want to hurt anybody's feelings, if they were attempting to be ferocious) and squeaked out a return "hello". (Here, I trusted my gut instinct that nothing was wrong, and that I wasn't receiving a warning. That's why I didn't ask for confirmation that it was okay to proceed, and it turned out none was needed. No squirrels rushed me again on that trail that day, and no other noises "happened" to get me to snap to attention. It was a "one-off" sound, and I'm pretty sure, for reasons I don't feel like going into here, that it was a little boy BF, and you know how little boys are... But anyway, if you're ever UNsure, ask, ask, ask, ask.....)
So I'm just saying it can be hard to know, sometimes, exactly what they're trying to convey with their sounds. You could be right, that someone was pissed off. But it could also be that someone was SHOWING off, or just saying hello. With the new baby there (they love babies -- who doesn't?), and with YOU there, I'm thinking the likelihood is they were saying hi.
But maybe something else was going on. Can be hard to tell sometimes.