What you (ProdigalSeeker) are referring to is mostly extreme scenarios, and no one here who has argued for the expectation of giving toddlers leeway and freedom in the service has suggested these extreme scenarios as part of their argument. It has been stated explicitly that toddlers running on, damaging, displacing or defiling the altar (let alone in a funeral) is beyond reasonable behaviour. So you may can-it with the exaggerated scenarios.
Higgs is reading my mind, as usual. Tolerating short outbursts of noise, or the coming-and-going of parents is a resonable expectation of the congregation. Most of the time, and from the position of most of us here, parents are far, far more sensitive about their kids' behavoiur than not. If my son starts screaming like a madman because we've made the altar area off-limits, no one is more aware of his disruption than I am. And again, most parents are equally as sensitive. If the outburst is a 10-second protest, we stay and I think it's reasonable to expect and ask the congregation to tolerate it and move on. If it turns into a full-fledged tantrum, off we go for a few minutes until he's calm and we come back. And if that happens twice, then people should appreciate that I'm removing him from the situation and should tolerate my coming and going.
I think the congregation should also be, or learn to be, ok with a toddler wandering around, exploring the space; flipping through the books (which includes dropping them once and a while), or dancing/swaying to the hymns and service music while it is on.
Parents should realize when enough is enough and not permit extended howling or shouting without withdrawing to calm the child down, just as they would in most public or social spaces. If the toddler's wandering turns into climbing through the pews or attention-getting measures such as tugging on people's clothes, etc, they should reign the child in to establish a difference between physically bothering people and just exploring. The congregation should accept the learning process involved and realize that a minor distraction from time to time is well worth having the little one around.
Silent toys, mats, etc to hold their interest and minimize the other activities that cause distraction, (like wandering around, climbing on things, etc) should be provided, or at the least, welcomed if the parents bring them in.
In my previous parish, the people made the conscious and intentional decision to be an open parish to young families. For years they had said constantly "we wish we had more children and young parents." But only when a new rector came in and challenged them, spelling out the things that they would need to commit to in order for that to happen, did it become a reality. It was not easy for everyone but the benefits were immense. Many of the older people in the church would often take a screaming baby off of a parents hands and rock it in the narthex, both for the joy of holding a baby but also to give the parents a moment's respite from new-parent life. The young parents interchanged as child-supervisors on the mats up front, and the noises of little feet on the tiles as they wandered around were less and less noticable as time passed, despite there being more and more children. We were blessed further with a very child-friendly priest (which is not an expectation, but a gift), such that when the babies would crawl up to her while she preached, she would pick them up and continue on.
The "complaints" of intolerance in this thread, I think, have nothing to do with extreme cases. What I think is unfair and even sinful, is for anyone to be "glaring" at anyone else for some minor disturbance. Such an action is mean spirited, impatient, and hateful. Doing so just because a toddler is walking up or down the aisle, or because they are turning pages of a book during confession, or because they speak up and ask a question to their parents is a really horrible thing to have happen in a church.