Whatever the motivations behind these responses, all I can tell you is the overwhelming message that's coming through to me from them seems to have a really dark subtext about not getting ideas above my station if I want to work, breastfeed and keep my child healthy.
You may read it that way, but I see it as practicality.
If you can't take a few months out of your life while your baby is young to have short trips so you only need to express smaller amounts which can go in hand luggage, then, perhaps, either the job, or the baby feeding method needs to change.
Many of us here work, travel, and BF young babies. We looked at our options, and picked the ones that would sensibly work - be that a nanny, travelling with the baby, short trips for 6 months, different method of transport, or formula. Rather than 'I'm alright Jack' it's that we've been there, thought it through, and on balance can't support the petition on that basis.
As to the cost - if an MP is paid 76k, if they work 40 hours a week, 48 weeks of the year (this may or may not be correct) then for every hour one MP spends looking at this issue, one more of these very rare women could have checked a bag. A checked bag that it is the responsibility of their employer to pay for if they are travelling on business.