I would not say that this answer explains away what could be a "2nd blessing", but it is the interpretive basis for that conclusion. The answer lies in the hermeneutic "examples found in historic narrative are not necessarily normative for the Chruch". Simply stated, just because it happened once does not mean it's supposed to happen that way every time. The classic case of when this hermeneutic is ignored is the Appalachian Snake Handlers who think that because Paul was bit by a deadly viper, "however, shook off the creature into the fire and suffered no harm" (Acts 28:5) then all Believers should be able to do the same thing. Unfortunately there has been as many as 120 confirmed deaths from snakebite in this group of people.
So, by applying this hermeneutic, the reader must agree that certainly Peter and John had to pray for and lay hands on this group of believers before the Holy Spirit came upon them, but is there any other evidence, particularly in the epistles, that would lead to the conclusion that the receiving of the Holy Spirit is only (or even usually) accomplished this way?
When we examine the rest of the New Testament, there doesn't appear to be much to support that.
For example, Paul wrote a lot of letters to the Church, explaining a lot of theology and giving a lot of instruction on how things are to be done. There does not seem to be anything he wrote about a "2nd Blessing". However, he did write "Anyone who does not have the Spirit of Christ does not belong to him" (Rom 8:9). So evidently, if you belong to Jesus then you have the Holy Spirit.
I trust that I am accurately stating the cessationists take on it.