Yes, but like most things in life, an important balance between too much and too little exists. Shorter block times make it harder for <50% attacks to succeed, true, but by increasing the number of orphans, it decreases the effective hash rate of the network, making a >50% attack potentially much easier. Bitcoin considers the potential risks of a successful >50% attack to be very high, so Satoshi chose a long block time.
This seems like mathematical nonsense, please prove to me that for example if there are 4 times more chain splits with 1/4 the block time, that there are less iterations to arrive at consensus within the same duration. I bet you can't, because the increase in chain splits is trivial compared to the increase in blocks.
LTC has certainly proven for a long time that a shorter than 10min block target is perfectly viable.
Of course a block time shorter than 10 minutes is perfectly viable! I never said that it wasn't. My point was that there exists a point where the orphan rate caused by a shorter block time ends up outweighing the benefits of a shorter block time. This starts to matter earlier than you may think because an orphan rate of just a few percent would be enough to encourage miners to centralize. However, ignoring that, here's an extrapolation of the reduction in effective hash rate as a network the size of Bitcoin reduces block time (the Bitcoin network currently sees about a 1% orphan rate):
| Blocktime in seconds | Reduction in effective hashrate |
| 600 | 1% |
| 300 | 2% |
| 150 | 4% |
| 75 | 8% |
| 37.5 | 16% |
| 18.75 | 32% |
| 9.375 | 64% |
As you can see, two and a half minutes per block isn't actually all that bad in the reduction of effective hashrate, but I wouldn't want to go much lower than that.