This question is addressed to Protestants

Infant Baptism is admitted to not be Biblical at all. In fact, the model of baptism(Jesus Christ) doesn't allow it. Jesus is our model for baptism. An infant cannot consent to Baptism. Here's why:

BIBLICALY SPEAKING, you have to become a disciple(student), believe, repent and embrace Jesus Christ before baptism. An infant cannot do that. An infant has no idea what is going on. Therefore, infant baptism is not recognized as Biblical.

An argument is made by some in favor of infant baptism. They refer to the instances where ‘households’ were baptized, such as the households of Cornelius, Lydia, the Philippian jailer, Crispus, and Stephanas. (Ac 10:48; 11:14; 16:15, 32-34; 18:8; 1Co 1:16) They believe that this implies that small babies in those families were also baptized. But, in the case of Cornelius, those who were baptized were those who had heard the word and received the holy spirit, and they spoke in tongues and glorified God; these things could not apply to infants. (Ac 10:44-46) Lydia was “a worshiper of God, . . . and Jehovah opened her heart wide to pay attention to the things being spoken by Paul.” (Ac 16:14) The Philippian jailer had to “believe on the Lord Jesus,” and this implies that the others in his family also had to believe in order to be baptized. (Ac 16:31-34) “Crispus the presiding officer of the synagogue became a believer in the Lord, and so did all his household.” (Ac 18:8) All of this demonstrates that associated with baptism were such things as hearing, believing, and glorifying God, things infants cannot do. At Samaria when they heard and believed “the good news of the kingdom of God and of the name of Jesus Christ, they proceeded to be baptized.” Here the Scriptural record specifies that the ones baptized were, not infants, but “men and women.”—Ac 8:12.

A lot of protestants do not believe baptism is necessary for salvation. It all depends on a careful interpretation of John 3:5

"Jesus answered, Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God."

Now, "born of water" could be (and probably is) a euphemism for physical birth. The reasoning is thus: Christ is talking about being born twice. Nicodemus says "How can you be born twice?" If being born of water meant baptism, and there was another birth of the Spirit, then you'd actually be born -three- times.

Clearly, from John 3:3, we are talking about two births, not three. Therefore, "born of water" is a euphemism for physical birth and born of spirit is being born-again in Jesus Christ. This is what many evangelicals believe.

HOWEVER- I also believe people should get baptized, and there may be spiritual power in it because Christ underwent it, and it's been a tradition for so long and it would be really dumb to go to hell over the technicality (although I do not understand my God to be one to judge on something like that). All the same, why risk it? Jesus did it, let's do it too, if nothing less than to honor the way he showed us.

But necessary for salvation… strictly speaking, probably not, but play it safe anyway, cause' its eternal life we're talking about here.

Play it safe argument applies to infant baptism too. It doesn't hurt anyone if it's ineffective, at worst it's a public ceremony to dedicate a baby to Christ, at best it actually has a saving effect. Either way, why not do it and hope it has spiritual impact?

Because it leads to people not being actually baptized. There are likely millions of unbaptized people right now who think they were baptized due to that deception.

So? Tell them to get baptized again. That's the benefit of the mainstream + baptists.

Also- here's the problem with adult baptism argument: are you arguing an adult with the mental faculties of a child can never get to heaven? Which IQ, precisely, allows baptism to take? Or is it puberty- could we inject a child with testosterone or estrogen, and then baptize them?

It leads to problematic questions, and Christ just wasn't a legalist when it came to entering the Kingdom of Heaven.

You have to be born again in the spirit for sure, but it seems incongruous and Pharisetical to require specific rituals when he spends the whole New Testament pointing out how slavish obedience to ritual is meaningless.

They were under the old covenant. The new covenant didn't start until Jesus said "it is finished" and gave up his spirit.

How'd they get to heaven under the old covenant when there wasn't a heaven promised under the old covenant?

Now THAT is silly. The Centurion was, presumably, a pagan, for Paddington Bear's sake

It's not baptized again though. It's baptized for the first time. And maybe you missed the part that salvation is by grace through faith. It is not based on what ordinance you followed, those are expected of people who are already saved.

Salvation was always promised.

Genesis 3:15
And I will put enmity between thee and the woman, and between thy seed and her seed; it shall bruise thy head, and thou shalt bruise his heel.

You're reading an awful lot into Genesis 3:15…

I'd be careful there, virtually all ardent paedobaptist denoms like the Presbyterians (bless you guys) would rather implode than assert that physical baptism saves or justifies.