Minus Userpoints for down votes
As I mentioned on this answer already: I guess one of your problems is to determine wether upvote insert rule or downvote insert rule was triggered - vote up/down is storing this in two separate voting sets. (I might be wrong here, when I am good for you).

Let's say it is just one vote set and there are minus votes. you would have to adjust the positive check in the condition to a negative points check. I had my rules still in the environment so I cloned them and did those changes:

(minus points will be probably just negative grants.)

Event: User votes on a Node

Condition: User has role(s)
Parameter: User: [vote:user], Roles: authenticated user

Condition: Check the value of the vote
Parameter: Vote: [vote], Operator: is lower than or equal to, Data value: 0

Action
Grant points to a user
Parameter: User: [vote:user], Points: -3, Points category: General, Operation: Insert, Moderate: Use the site default


Export:

{ "rules_substract_down_voter" : {
    "LABEL" : "substract down voter",
    "PLUGIN" : "reaction rule",
    "REQUIRES" : [ "rules", "voting_rules", "userpoints_rules" ],
    "ON" : [ "voting_rules_insert_node" ],
    "IF" : [
      { "user_has_role" : { "account" : [ "vote:user" ], "roles" : { "value" : { "2" : "2" } } } },
      { "voting_rules_condition_check_vote_value" : { "vote" : [ "vote" ], "operator" : "\u003C=", "value" : "0" } }
    ],
    "DO" : [
      { "userpoints_action_grant_points" : {
          "user" : [ "vote:user" ],
          "points" : "-3",
          "tid" : "0",
          "entity" : [ "" ],
          "operation" : "Insert",
          "display" : 1,
          "moderate" : "default"
        }
      }
    ]
  }
}


So there are still some things for you to check:


does vote/up down use one or two rule sets?
if it uses two, how to determine that in rules?
if it's only one with negative votes than you're done.