I actually agree with you about Robin's statement that "Baptists don't deduce." Not that I don't understand what they mean by saying that.

Without saying too much I thought I would quote from a book written by Samuel E. Waldron called 'A Modern Exposition 1689 Baptist Confession of Faith.'

Quote
Reformed Baptists embrace the unity of biblical revelation and God's covenantal dealings with his people. They insist, however, that an accurate idea of God's covenant dealings actually requires believer's baptism. The Reformed Baptist response admits that in the unity of God's covenantal dealing, there is a certain parallel or analogy between circumcision and baptism (Rom.4:11; Col.2:11-12). Both are rites or symbols of introduction into the covenant people of God.
Pages 437-438.

Waldron goes on to explain if paedo-baptists could clearly establish their argument for infant baptism from circumcision and the old covenant, then we should embrace it.
Paedo-baptism arguments logically assumes not just the unity but also the identity of baptism in the New Covenant and circumcision in the Old Covenant.

It is true that we can use good and necessary deduction about a doctrine like the Trinity, because it is clearly taught. However, we cannot say the same thing about infant baptism.

Please understand I am not giving this information for debate purposes. Rather, I am giving it in order to better understand Reformed Baptist argument on the issue.
As I read the book written by Waldron, it is very clear that he has enormous respect for Reformed Paedo-Baptists. Both Reformed Paedo-Baptists and Reformed Credo-Baptists, have more in common with each other than they have against each other. This is clearly seen in how similar their confessions are to each other. For example the WCF and the LBCF 1689.

Hopefully this gives a little more clarity to what Robin said.

Robin, have I accurately reflected what you meant?

Tom