Great post. I was wondering; do you have an answer to that question “why?” I must admit that this question bothers me.
Well I don’t know that I have an answer that will resolve the matter for you but I do have some answers…
Why is it that this has been elevated to the level of dogma?
Well the reason something is elevated to the level of a dogma is in order to settle some (controversial) question for the universal church. A dogmatic declaration is made because, after much debate and deliberation, and recognizing the grave responsibility attached to the authority to bind and loose whatever, “It seemed good to the Holy Spirit and to us (Church leadership)…”(Acts 15:28) to do so.
I understand that Mary might be the shortest way to Christ, but the entire system of praying to the saints seems superfluous to the central claims of the Gospel.
Well - It is and it isn’t…Prayer to the saints is permissible but is not required. Looking at the dogmas related to the intercession of the saints
HERE, not the use of the phrase, “It is permissible and profitable…”, these dogmas do NOT say that it is required.
Does this make veneration of the saints and prayer to and with the saints superfluous?
I don’t think so - unless you think that asking me or any other fellow Christian to pray for and with you is superfluous. Unless you think that recognizing great holiness in another and seeking to emulate that person is superfluous.
And for the life of me, I cannot figure out why certain claims about Mary have been made dogma.
Well - as pointed out above, this is often done in order to settle some controversial question.
And so I ask “why this way of honoring Mary and not another?”
Now one gets into more of the grist of the matter - which “way”…

…???
This is where I get into trouble with some of my fellows here who are committed to a certain “way” and can become rather adamant in their promotion of a particular way.
Mostly when I comment on these matters it is in relation to those entering the Church who are struggling with the concepts and devotions. So I take the pains to point out that the methods are a matter of private devotion. That if they are uncomfortable with intercessory prayer they should not push it. Keep praying in the way that they are most comfortable with. the Holy Spirit will lead them where they need to be.
I think many of my friends reject Catholic veneration of Mary because they know what would happen. Through no fault of the faithful, others would take it to the point of idolatry. I know that proper veneration of the saints is a good thing; however, when I hear stories of individuals burying an icon upside-down in their garden in order to make the tomatoes grow, I know that this is the unavoidable consequence of praying to the saints. If I were to become a saint, I would not want anybody falling into idolatry because of a misunderstanding of what it means to ask for my intercession. I would rather everyone of them pray to Christ himself then even one person asking for my intercession to cross the line into idolatry.

…Had to laugh about the “upside down icon”. I hadn’t heard that one before. Maybe I need to do that since my plants are heavy with fruit but they just don’t seem to want to ripen…
Seriously - God winks at such things because He is a loving father and recognizes the needs - sometimes “silly” needs of his small children.
That said, I don’t think that the possibility of some taking something to excess is reason to go so far the other direction that one loses the benefit. Does it make sense to become anorexic just because some people get fat?
This example is, of course, extreme but if we think of those who slip into “idolatry” as “overeating” and becoming obese, then those who vehemently oppose saintly prayer and veneration are like those who become anorexic. We know that anorexia and obesity are BOTH unhealthy. So the need is for a proper balance.
Most important there is a need to recognize that, like with food, these are things that we need - are healthy and useful and enriching - when properly and responsibly utilized.
Sorry if I have rambled off here…I hope some of this makes sense…
Peace
James