Actually Humor includes things like "delivery" and "timing" as well as visuals etc. and differences in those facets can make sarcasm (or other form of Humor) objectionable or funny. So even with sarcasm one cannot claim it to always be "good" or "bad".

In the OP's three examples, all three involved someone butting into the conversation of others which, in itself, is rude (a delivery problem) and thus weakens any possible Humor by making the speaker sound like just some needy little person wanting attention so badly they are willing to rude others to get it.

"Bad" sarcasm is best typified by sarcasm aimed at a person present, or known among those present. The person who verbally batters their spouse with sarcastic insults is the prime example. Another would be the forum member who posts only caustic, non-helpful remarks to the threads started by others.

An example of "good" sarcasm (or at least not-so-bad sarcasm)could be when the "hurt" or "insult" is aimed at a group or entity that is chiefly apart from present company or personally known persons ... as when Will Rogers said: "This is the USA. We have the best politicians money can buy". A few levels higher in refinement would give us Garrison What's-his-name telling us that all of Lake Woe-Begone's children are above average which is the incongruence of "all" and "average" as well as a gentle spoof of parental pride.

Unfortunately, people who have grown up with Television have been saturated with horrid interpersonal sarcasm by the scum that run Television and now we have many unthinking people who actually believe the insults and hurtful remarks so common to TV sitcoms are actually funny. Sadly, insults comprise 99% of what they call their "dry sense of Humor" and they inflict themselves on everyone around them like large, stupid fleas. It is those acid-mouthed dullards who are difficult to abide and great fun to avoid.
The shame is that mentality (or perhaps unmentality) has fueled the "battle of the sexes" to the point where it has become a very destructive force in our Society. It has also been an impediment to improving race relations. Thankfully, not everyone buys into the Don Rickles mindset.

Local opinion(s) may vary.