nobody searches, nobody cares somehow

To all those Christian pastor/leaders types who advocate giving a tithe of 10% of your gross income to your local church :

If I'm a UK taxpayer, and I helpfully fill in the Gift Aid declaration and standing order form, can I give 10% of the net and Gift Aid it? Or do you want 10% of my gross PLUS Gift Aid?

So much legalism, so little time.

I just don't understand, if their message is : - "Oh yes, of course we are all under grace now, so we can give what we like, but if we gave 10% under law just think how MUCH MORE grace will give, so that is why we say give at the very minimum a tithe of 10% of your gross income to your local church, but of course, you should give more, give cheerfully, God loves a cheerful giver, did you know that the original Greek meaning for the word translated here as "cheerful" means hilarious? Anyway, you don't HAVE to give. But, you know, really, ... givety give give!!!" - why do they have to continue using the language of the law?

Why is my financial gift a "tithe" when it isn't a tenth of the increase in number of my livestock, or a tenth of my harvested crops? Why is it a "tithe" when I'm not giving it to the tribe of Levi to allow them to continue the temple system of sacrifices and offerings?

Why do they tell me to "tithe" by quoting a prophecy that said to the Israelites "Follow my decrees, including the full payment of tithes, honour me, and I will give you the Messiah" ? I thought we already had Him.

Why do I even think I've interpretted this better than them? What right do I have to say anything, to them, to anyone else? Why does it have to be so complicated?

Why can't we just give? Give intelligently. Give unintelligently. Give in proportion. Give in excess. Give money. Think about it first. Don't think about it. Give time. Give food. Give things. Give to God. Give to church. Give to charity. Give to others. Give to help. Give to serve. Give to worship. Give to love.