pastors lie and are not struck dead. why not?

I feel sad for Ananias and Sapphira.

I do not understand. It is most unfair. Megachurch pastors lie to collect 10% of our income but they are not struck dead. Why not?

The megachurch we were attending until a few months ago (http://www.chapel.org) has gotten around the tithing lie by not calling it a tithe, but saying "we should give at least 10% of our income to God". It is their requirement (one of three) for all members. 2 Corinthians Chap 9 says we should give what we have decided in our hearts. 

Nowhere does it say "at least a tithe". so why do these pastors get away scot-free?

Acts 5:1-11New International Version (NIV)Ananias and Sapphira5 Now a man named Ananias, together with his wife Sapphira, also sold a piece of property. 2 With his wife’s full knowledge he kept back part of the money for himself, but brought the rest and put it at the apostles’ feet.
3 Then Peter said, “Ananias, how is it that Satan has so filled your heartthat you have lied to the Holy Spirit and have kept for yourself some of the money you received for the land? 4 Didn’t it belong to you before it was sold? And after it was sold, wasn’t the money at your disposal?What made you think of doing such a thing? You have not lied just to human beings but to God.”
5 When Ananias heard this, he fell down and died. And great fear seized all who heard what had happened. 6 Then some young men came forward, wrapped up his body, and carried him out and buried him.7 About three hours later his wife came in, not knowing what had happened. 8 Peter asked her, “Tell me, is this the price you and Ananias got for the land?”“Yes,” she said, “that is the price.”9 Peter said to her, “How could you conspire to test the Spirit of the Lord? Listen! The feet of the men who buried your husband are at the door, and they will carry you out also.”10 At that moment she fell down at his feet and died. Then the young men came in and, finding her dead, carried her out and buried her beside her husband. 11 Great fear seized the whole church and all who heard about these events.