Bright day

1) Does sniffling or clearing the throat remind you of any particular
person? If you can't think of anyone, maybe your parents know
of someone you've been around who used to do it a lot?
Perhaps there are some feelings towards a person who does this involved.

2) Do you experience images of spit or snot when hearing these sounds?
Then maybe you can begin to overlook them.
Or does it give you a feeling physically of doing so yourself?

3) What could you actually say to a person doing so about the sound?
I mean other than "it's disgusting" or "I can't stand listening to it."
Remember it's people who are doing it, and people are nice.
They have no ill intentions doing so. It's part of being around people,
so include it in that context - there are so many nice sides to being
around people, and this is one downside.

4) I could be that you generally in verbal communication rely to a
high degree on voice characteristics in order to perceive info
that is not directly expressed through the words. (Emotions,
motives, nuances in meaning etc.) While other people may rely
more on facial expressions and others yet may perceive the
words more logical-analytically.

Many schizophrenic persons process emotional qualities of voices
with both their left and right hemisphere of the brain, while the
majority of others mainly do so with their right hemisphere.
This might be related to bipolar as well, particularly since the
borders between the two diagnosis are somewhat arbitrary.
For me sounds often give a strong sense of personal characteristics,
attitudes, and personal motive. So I can understand that certain
sounds are perceived as in some way very intolerable.

I think too that anxiety sounds like it can provoke your responses.
But the emotional pressure that causes you to act out, I think
has very little to do with the sound, rather other issues. If you
work on those, your pressure to act out when hearing these sounds
will be reduced.

A suggestion that may sound repulsive:
Record the sounds on an mp3-player or see if you can find recordings of
the sounds on internet. Sit up straight in a relaxed and focused state,
and listen to the sound repeatedly, and learn to listen to it in a detached manner.

I used to be bothered by whistling. Because often it is musically very
insensitive. But I think it was a sort of fix idea as well. That I liked disliking it,
partly because of the response I got from speaking negatively about it,
when someone did it to tease me, and also that i enjoy describing and
imagining sounds.
Now I'm not affected by it. I try to think of that the person might be enjoying himself and that it's a nice person. I switch the focus from
listening to it as music / sound to thinking about the person. Or I don't pay attention to it.

Anyway, I hope things will turn out nice for you.
Have a lovely Sunday!