I can see why people were miffed. Your social circle has a fairly well established routine - dinner and drinks, the birthday person gets treated, and this cycles through the group so it balances out over the year.
Todd then takes it on himself to try to organize a birthday week extravaganza for his new squeeze, that manages to quadruple the normal amount of celebrations (four distinct, pay your your own way events, at which you may or may not be expected to chip in for the birthday girl). His justification for this - his GF is so awesome that she deserves this.
So I think the reason why people were put off by this was 1) the sheer amount of time and money they were being asked to spend on one person's birthday and 2) the love-struck implication that she was more worthy of celebration than the rest of you and 3) the disruption to what had been a very workable routine. Instead of one birthday gathering, you have four, and most people aren't going to go to more than one or two, so the celebrating as a group tradition gets shot down.
I would say Todd was more clueless and lovestruck than really outrageous, and just not thinking. If he had thought, he'd have gone with the usual group celebration, and taken his GF out for a nice dinner or skating with just the two of them later that weekend. And in both directions people behaved correctly in that they didn't berate people for not showing up, and you guys didn't complain to them about the invitations, but simply accepted the ones you were interested in.