Absolutely with you there OP, despicable system.
Whether male or female it always seems ok for a parent to absolve themselves of the responsibility for the children they have created. My EXH did the same.
Dealing with the CMS was traumatic, I could write a book. I was disgusted that as a serving police officer, he lied and blocked every attempt to get money from him, even though he was fully employed in a professional role and earning from a second business.
One telephone call the CMS staff member informed me that my EXH couldn't afford more than £3.00 per month against his £1,000's of debt. She said "I've been trying to contact him unsuccessfully this week to ask him if he can possibly agree to an increase of £5.00...but he isn't answering his phone". My response "no you won't be able to get hold of him, he's skiing in the Alps for 3 weeks". Unbelievable!
Given emotional abuse I was shocked to be expected to attend my appeal hearing with him, including a joint meeting and had to forgo the right to appeal in person as I just couldn't sit and argue over money with him ( with his OW accompanying him).
He claimed a higher amount as a deduction for his new partners DD who lived with them 50/50 than he was expected to pay for his own DC's. How does this work? This DD had two full time working parents earning £150,000 between them, why was my EXH allowed to priorities 'money' for someone else's child over his own.
With a full time wage and his £500,000 inheritance, maintenance for two DC's amounted to £211 per month, not enough to even cover their school lunch as teens. (not that he pays it)
I continued with my teaching job yet was able to claim tax credits and childcare. Why? Why are you, the tax payer supporting our DC's when he has the means to support his own DC's. Again sheer madness.
Dealing with the CMS was just about as traumatic as my divorce. Hour after hour, letter after letter, calendars of contact, diaries, witness statements,appeals, gullible CMS staff. Absolutely soul destroying at a time of trauma anyway, having to fight for something to which the DC's are entitled.