"#5 The measures impose no new tax, they merely seek to prevent avoidance of an existing one."
Not entirely true. Pension contributions for an employee are made before tax is deducted, working inside IR35 they are deducted after the tax, so yes, a new tax on pension contributions has been introduced. Legitimate Expenses are similarly impacted, for an employee they are deducted before Corporation Tax, under IR35 expenses are covered after the tax has been deducted.
Jolyon Maugham has fallen into the trap that every person performing a role is on an equal footing when the reality is they are not. Employees and Contractors are engaged on different terms, and receive remuneration on different scales.
Employees have protections contractors do not, and employees receive a range of benefits that a contractor must account for out of the gross payment they receive (holidays, sick pay, etc is all part of the gross payment, contractors still receive them, just not from the client as part of the package).
IR35 specifically targets the little man, forces them out of the market and paves the way for the large consultancy companies. Take the money away from the people and put it back in the pockets of the rich.