Maduro IS blocking humanitarian aid. He'd prefer that the Venezuelan people die of malnutrition or lack of medicine so that he can stay in power:
From the NYT, 21 February:
" MEDELLÍN, Colombia — President Nicolás Maduro of Venezuela ordered its border with Brazil closed Thursday, part of his escalating effort to stop opponents from sending humanitarian aid into his poverty-stricken country.
Juan Guaidó, the parliamentary opposition leader who declared himself president of Venezuela last month, has vowed to bring tons of aid donated by the United States and others into Venezuela on Saturday. Mr. Maduro, who has called Mr. Guaidó an American lackey, has vowed not to let the aid in.
The Brazil-border closure, announced on television, followed a Venezuelan government
announcement on Wednesday that it would block air and sea travel between Venezuela and three Caribbean islands where the opposition said it wished to stage relief supplies.
“It’s better to prevent than to regret,” said Mr. Maduro."