That word means different things to different people. For some it means affirmation for every aspect of the tribe or nation and derogation to every aspect of other tribes or nations. We are the greatest in every respect, and all foreigners are inferior. Above all we can never trust a (treacherous) foreigner.
Blake's patriotism is of a different sort. He loved his country and wanted and hoped for the best for his country, and deplored the worst of it-- like the slave trade, the imperial wars, the fantastic wealth and abject poverty which fed off one another, the 'mind-forg'd manacles'.
He loved America; it represented in his mind the freedom which he longed for for his country. He's said to have been present at the Newgate riots in which "many were avowedly pro-American independence".
Those of the Establishment would no doubt have considered this the opposite of patriotism; for some of us not so .
The French Revolution came along in the nineties, and Blake wore a red cap; but when the guillotine became part of it, Blake took off his red cap. In the thirties political revolution no longer had a positive value for Blake.
"But vain the Sword & vain the Bow
They never can work Wars overthrow
The Hermits Prayer & the Widows tear
Alone can free the World from fear
For a Tear is an Intellectual Thing
And a Sigh is the Sword of an Angel King
And the bitter groan of the Martyrs woe
Is an Arrow from the Almighties Bow
The hand of Vengeance found the Bed
To which the Purple Tyrant fled
The iron hand crushd the Tyrants head
And became a Tyrant in his stead"
(From The Grey Monk)