If you are sending out a lot of connection requests, you will get a small amount of people responding that are upset. If your message is relevant to a focused audience, this should be perhaps 1 person in a thousand. Respond POLITELY and provide more information about yourself. About half of the time I end up in good conversations with these people. Some responses will be puzzling. “I don’t want to have a conversation with you because I do not already know you.”  Clearly this person has missed the point of networking. A few people are just jerks. Search for their name and disconnect them.  Go to your My Network tab. Click on Connections. Click on the three dots and then remove the connection. This is also a good way to remove competitors that are currently somehow connected with you.