Why is it a big deal that the corn industry is getting about a 3.6% subsidy from the US Government?

I'm reading that the corn industry is $90B/year in the USA, and that they receive about $3.2B/year in subsidies

• Why can't the USA just waive them from paying taxes instead of subsidizing them in the first place? I'm sure that the admin work would be less by making this a not-for-profit type of industry that doesn't have to pay federal taxes.

Why do people think that this 3.6% subsidy is very unfair, when it is, in my opinion, not that big of a deal?

• Since the subsidy is so small, why can't the USA simply pull the plug on it anyways?
• It seems like if the subsidy were removed, the prices of corn products would only go up by 3.9% (1/(1-0.036)) . Economists are big into governments not intervening, so this would strengthen our small, limited government posture. So why can't we remove it, since it doesn't seem to detrimental to me?