Rosslyn,
I wasn’t at this Mass, so of course I can’t speak for the ‘lack of a sense of sanctity’ that may have been present, but before you conclude it was ‘one of the worst Masses ever’, you might take a second to ask whether what you perceived as a lack of sanctity was, in fact, a Mass according to the rubrics…
The rite of baptism, in the context of Mass, begins with the rite of the reception of the children to be baptized. It is supposed to take place at the doors of the church.
#29 of the Rite of Baptism for Children states that, following the rite of reception, “the greeting and penitential rite are omitted.” Therefore, if by ‘brief prayer’ you mean the collect, then this is proper.
Although an exposition on the readings is typically part of a homily, it is not strictly required, per se: “[the homily] hould be an explanation of some aspect of the readings from Sacred Scripture or of another text from the Ordinary or the Proper of the Mass of the day and should take into account both the mystery being celebrated and the particular needs of the listeners” (GIRM #65). On 'Mission Sunday", then, it’s not too surprising that the homilist talked about fund raising for the missions.
You ‘sat through’ them? As in, “oh, what an inconvenience”? The general introduction to the rite of baptism would disagree with you: “In the actual celebration [of baptism], the people of God (represented not only by the parents, godparents, and relatives, but also, as far as possible, by friends, neighbors, and some members of the local church) should take an active part. Thus they will show their common faith and express their joy as the newly baptized are received into the community of the Church.” So, the intent isn’t that you simply “sit through” it, but actively participate (through silent prayer, verbal responses) and express your joy that Christ’s Church has gained new members!
On the contrary: you seem to have ended up at a Mass that was properly celebrated according to the ritual of the Church.