Although, people are rarely "read of out meeting" anymore. And even back "in the day," someone who had been read out of meeting could not participate in the meeting for business. Meeting for worship and all other fellowship was not restricted. Some more separated meetings may have done more than that, but for the most part, that was it. More strutured shunning was and is left to the Amish, not the Friends. And still, reading someone out of meeting is reserved for unrepentant people, following the process of church discipline.
If a person is unrepentant, then such exclusion is not unwarranted. In such a case, the person has, themselves, made a choice to refuse righteousness and take the wrong road. We are to be available to them when they come back on the right road, but if not, they've made a choice
Personally, any church that would read me out of meeting, or exclude me in light of my repentence and restored walk with God, well, I wouldn't want to be in such a place anyway. Bottom line, no great loss, except for the people doing the excluding.
Oh, I wanted to go back to the examples given. If the reason we employ church discipline is because of habitual sin, then if, in the two cases above, the sin is not continued after it is called out and repented of, there is no reason the disciplined people cannot be restored to fellowship. It may be hard for the others in the church, having dealt with the issues leading up to the discipline, and the whole church may have to do some (a lot of) readjusting and trust building, but it can and should be done.