Boolean.parseBoolean("1") = false...?

It accepts only a string value of "true" to represent boolean true. Best what you can do is

boolean uses_votes = "1".equals(o.get("uses_votes"));

Or if the Map actually represents an "entitiy", I think a Javabean is way much better. Or if it represents configuration settings, you may want to take a look into Apache Commons Configuration.

I have a small utility function to convert all possible values into Boolean.

private boolean convertToBoolean(String value) {
    boolean returnValue = false;
    if ("1".equalsIgnoreCase(value) || "yes".equalsIgnoreCase(value) || 
        "true".equalsIgnoreCase(value) || "on".equalsIgnoreCase(value))
        returnValue = true;
    return returnValue;
}

According to the documentation (emphasis mine):

Parses the string argument as a boolean. The boolean returned represents the value true if the string argument is not null and is equal, ignoring case, to the string "true".