Net neutrality favors any entrant equally, and thus is unfavorable to the large tech players (all of whom can financially overcome any obstacle).
deregulation, a free market economy, and a small government
Right, and that is total bullshit. State rights is a supposed principal of the Republican party, until a state wants to do something in opposition (seen time and time again, and already evident with net neutrality -- if California and New York state demand NN, it will turn the whole thing into farce leaving the hillbilly states reaping what they sow). Republicans love free market, unless it's the free market threatening the incumbents.
unless you really think that Alphabet, inc. is on the side that opposes big businesses
This profoundly and comically misreads the motives of the big tech players.
The GOP is for states rights, and they are also for the general decrease in government size. They are against state-level NN because that is increased regulation in those states. There are legitimate exceptions (gay rights, abortion rights, war on drugs, etc.), but those apply more to social issues than to economic ones. In terms of free market policy, the Republican party has a pretty reasonable track record of supporting it. For example: https://www.whitehouse.gov/briefings-statements/president-do....
Net neutrality is 100%, unequivocally favorable for every tech company (Google, Facebook, Netflix, Twitter, Microsoft, etc.). Are you sure the Democratic party is not the "voice of the oligarchy" here? You say that Republicans are incapable of building justification for this decision, but it fits exactly to the pillars of the Republican party -- deregulation, a free market economy, and a small government. Their argument is that NN is unnecessary regulation that limits the free market and oversteps the boundaries of a reasonable government. You may disagree with this, but that argument is a subjective one and not an objective one. It may benefit the providers but it also hurts the tech monopolies (which is why they oppose it so adamantly... unless you really think that Alphabet, inc. is on the side that opposes big businesses).