Being able to complete the duty means what? Back in the day, parties wiped many, many times to Titan HM. Is one wipe enough to mean that a player cannot complete the duty? Are two wipes enough? Where do you draw the line?
If we are talking about things in the MSQ, or light party content, or normal/hard mode (not raid or alliance) content, then I think that such judgements have no purpose. Because in general, parties are capable of clearing such content with ease, even with sub par performance. Titan HM being an obvious exception to that (at the time), and if you remember it was quite contentious at the time too...
For EX content, raids and alliance content I view things a bit differently because that is optional content, and by undertaking it you are accepting that it's a greater challenge and therefore better than average performance is expected. If you are framing your situation about kicking a player for poor performance in EX/raid/alliance content, I can see your point. If it's in 'ordinary' content, I do not.
However, I still feel that kicking for performance is a problem. On the other hand if you PF'd and made clear the expectations of the group, I don't see an issue because you clearly set the expectation. But, if you DF'd it, short of someone intentionally sabotaging your run, I think you need to be careful about insta-kicking because you think they are not performing well enough.
That's where the whole judgement aspect of the advice about whether or not performance is a valid reason to kick someone comes into play. It's not entirely cut and dried.
To bring this back to the original topic, and relate it to this discussion, using parsers in content outside of the EX/raid/alliance tier of content is pretty well pointless and open to abuse. I say this because the fundamental truth of the topic is this; With or without a parser, with or without a coach, with or without being berated over performance, players who want to improve will seek ways to improve and players who do not, will not. Parsers won't change that. I think we all know that this is true.
The discussion about kicking people is really a distraction in this topic. Perhaps people are trying to find a justification for having public parsers so they can valiate their reasons for kicking people? Perhaps it's just about a distorted example to justify the presence of a parser? I don't know and I don't really care because those who want to improve will, and those who do not will not. Parsers and/or kicking people in DF over performance, will never change that.
Since that team is random, you cannot have any reasonable expectation other than warm bodies holding controllers. That is the point of DF, it's for everyone, whether they are good, bad or indifferent, whether they play like pro-bros or newbies. It's everyone and DF exists explicitly for that purpose.
You do realize that Party Finder is for what you want, and Duty Finder was created so that players without a group could at least find warm bodies to fill the roster right?