I work as a tax specialist. What you said is categorically not true. You can make as many ideological statements as you like; they have no bearing on how corporate taxation works in reality.

It is only tax evasion if the code is explicit enough to rule it out as allowable behavior...a feat of endurance for tax authorities. Even then, many legal tax avoidance behaviors would be non-existent or drastically less common if it weren't for corporate taxation.

The tax code includes provisions allowing enforcement authorities (generally, the IRS) to take the "spirit" of the law into account when evaluating a transaction, structure, or tax return. This means that something can be completely kosher under the letter of the law but still be treated as tax evasion if it violates the spirit of the law. The 90's off shore tax shelters are probably the most notorious example of these. Nearly all tax evasion schemes are centered around individual taxpayers. Not many people are willing to put their own necks on the line to facilitate widespread corporate tax evasion. (And indeed, individual non-compliance is estimated to be more than 4x the size of corporate non-compliance in the US as a matter of unpaid tax liabilities.)

If your corporate lunchroom is subsidized (extremely common in mid to large size corporations), it is likely because that subsidy is tax deductible, whereas an individual purchasing their own lunch is not.*

Companies absolutely do not subsidize lunches or healthcare for the tax savings that accrue to the employees. They do so because because such subsidies are financially beneficial from a business perspective (i.e., employee recruiting/retention).

Compliance and enforcement costs are roughly proportional to the cartesian product of the complexity of the rules and the number of entities.

Definitely not true. Compliance costs are roughly logarithmic. Scale increases disproportionately at mid-size companies but once you approach multinational status the increase in the number of entities results in significantly less than a linear increase in costs. The advantage of scale is a primary factor in the structure of accounting firms.

Sure, pushing taxes onto shareholders increases the number of entities, but drastically reduces the number of rules, due to the fact that personal income tax is not a profit tax.

Hahahahaha. Pushing taxes onto shareholders increases the number of rules. You see a reduction in statutory laws but a vast increase in non-statutory rules (i.e., court cases and administrative decisions). It's very easy to keep track of statutory law; it's relative a nightmare to track non-statutory rules.

The corporate tax has to have millions of rules and exceptions to rules because businesses are drastically different and legitimate expenses for one business may be illegitimate for another.

This is not how the tax code actually works. A business expense is generally deductible regardless of the industry if the expense is legitimately related to a business need of the enterprise. Very few business expenses are not legitimate, though due to exceptional levels of fraud and abuse "meals and entertainment" and employee vacation expenses (i.e., paid holidays or vacation time) are usually not fully deductible by a business.

I totally understand that there are way more shareholders than there are companies, but the difference in the number of rules between corporate taxes and and the marginal increase in rules on personal income taxes easily makes up the difference.

Nope. Scale matters. It's easier and more efficient for the corporation to determine its tax liability than it is for an individual, and the corporation has greater resources to do so. You trade having a few thousand taxpayers spending an average of 10-1000 hours dealing with compliance with many millions of taxpayers spending 10-100 hours dealing with compliance. Definitely not a net benefit to society.