the conservatives designed a system where they use targeted tax cuts to reward voters that vote for them and punish voters that vote against them. whether we like it or not, such a system now exists. the liberals are simply playing by the rules the conservatives put in place. and, the ndp will do the same thing, too.
hopefully, a liberal government will smash the whole thing to pieces, in time; you don't get to change the rules from opposition. but this is legitimately the kind of thing you have to do slowly. harper has set up a system of state dependency to socially engineer voting patterns towards him; it's an abuse of power, really. it's less that cutting the cord is going to make voters angry. it's more that it's inhumane to do it without easing it out.
in the meantime, this is in the rule book. so long as it's there, it's reasonable to make it more fair and target it at the groups that actually deserve tax credits, rather than use it as a way to bribe already rich people into voting for them.
i know that if we want to break this election down to a choice between tax credits for teachers and tax credits for ceos, canadians will overwhelmingly make the obvious choice.
http://www.cbc.ca/news/politics/canada-election-2015-justin-trudeau-s-fuzzy-logic-on-tax-credits-1.3211998