Here's Dale Smith in his own comments section:
The Senate is almost never going to turn down a budget bill because they’re confidence measures, and the Senate is not a confidence chamber.And another commenter, James Bowden, in more stark terms:
There is no legitimate constitutional argument why the Senate should not be able to kill this private members’ bill. It is certainly not a matter of confidence and did not require the royal recommendation. The Senate poses no threat to the primacy of the Commons by voting against a frivolous private members’ bill.So the pro-Senate line is that a private members' bill which happens to win the support of a majority of elected members can be killed without any reason to think twice - just so long it's the result of mere elected MPs debating and voting on a bill on their own, rather than the approval of the executive branch. (And the fact that the bill under discussion didn't receive a lot of debate has everything to do with the reality that very little time is allocated to private members' business compared to government business.)
By that account, the limits of Senatorial authority would be seen to begin and end with a declaration that a bill is a priority for the sitting government (as a budget or confidence measure). Which looks to me to entrench all the more power in the hands of the PMO - even as the Harper Cons have given us nothing but reason to worry about the control our current executive exercises over both MPs as a matter of party discipline, and parliamentary procedures as a matter of preventing inconvenient votes.
Suffice it to say I consider it rather questionable that a constitutional relic intended to limit democratic decision-making from day one should be accepted as a reason to treat the legislative process in the House of Commons as being no more significant in deciding on the fate of a law which meets with the disapproval of a chamber of appointed hacks than a straw poll of the Parliamentary kitchen staff. And if our goal is to make sure that MPs do their jobs better, we'll accomplish far more by asking them to justify their their actions directly than by declaring that we're just fine seeing their work rendered meaningless by unelected Senators.