I'm not a Baptist, but have some relatives who are. And over the years I have become rather well-acquainted with them.
To begin with, there are all kinds of Baptists. The ABC - American Baptist Convention (formerly the Northern Baptist Convention; they split over slavery before the Civil War) - is a rather moderate group all in all. For example, it includes the famous Riverside Church in Manhattan.
Then there is the Southern Baptist Convention, with perhaps 15,000,000 members, the largest Protestant group in the USA. (But remember that you have to at least double most Protestant numbers because they don't usually include young children and those who are constitutents. For example, a church may lose 15 members by death in a year but the pastor may have 30-40 funerals. Etc.) The SBC is more conservative, often even fundamentalist, though it has a wide variety of congregations. And remember that each congregation is independent ultimately - calls its pastor, runs its own parish, etc.
Beyond that there are all sorts of other Baptist groups and totally unaffiliated Baptist congregations.
Some statisticians suggest that there may be as many as 50-60 million Baptists in the USA. This is about the same number as Catholics.
It is true that some Baptist clergy get into politics, just as some Catholic clergy get into politics. For example, at the mass I attended a few weeks ago an insert was enclosed in the bulletin asking parishioners to contact their state representatives to protest a bill in the legislature that would extend the amount of time for people to bring suit against the church for sexual molestation by priests. Baptist ministers may sometimes preach against abortion, as some Catholic priests do. They may denounce the courts when they try to knock out religion from public life, etc.
But historically the Baptists, unlike traditional Catholicism, was strongly opposed to any church/state connection. Rogers Williams founded Rhode Island in large part to get away from Puritan-run Massachusetts about 350 years ago. Catholicism often has sought preference in government. For example, under Franco, Spain promoted Catholicism and virtually banned Protestantism. In various Catholic-majority countries even today you might a crucifix in public school classrooms, etc.
Now, as for grapejuice. Many Protestant churches (Baptists, Methodist, UCC, etc) traditionally were temperance churches and discouraged drinking (and often smoking, too). Moreover, and perhaps more important today, they wanted worshipers to be able to receive communion without any risk to alcoholics. So, grapejuice. A few churches offer both. In the Catholic Church, of course, usually few parishioners take the wine so an alcoholic need not be at risk.
One old sort-of-joke re Southern Baptists. What do Southern Baptists do when they meet other Southern Baptists in a liquor store? Pretend they don't see one another.
Baptists more than most mainline Protestants usually have less liturgy, more vigorous gospel hymns (some we sing in Catholic churches now!), longer sermons, and more Bible exposition. In their church government, they are congregational - that is, congregation controlled.
I love the Baptists. I love the Catholics. Didn't Christ tell us to love one another? I'm quite convinced that God looks at our hearts and not at our church affiliation.