im talking about blocks, not txs.

that would be just rejecting the block, would split the chain, create a network fork.

PoW favors the longest chain, by delaying it for a few seconds at each node, you are giving a chance for other miners find another block.

and because their block will be known earlier in the network, other miners might just build on top of it instead, since they heard about it first. giving it a chance to be the longest chain instead.

if no other miner finds a block in that time frame you still go with the earlier block. and even if another miner finds a block, you will still favor the longest chain.

so you just act like you didnt heard about it for a few seconds, like there is a network delay.

something similar already happens when a miner/pool manually includes txs to the block that nobody on the network never heard about before. since nobody heard about those txs they have to ask about it to each-other and the miner, making propagation of that block slower. and in that time if another miner finds a block at the same time which doesnt have manually added txs, their block will propagate in the network faster making the other block invalid.