Strategically, it makes no sense to corner and threaten people. Murdering their own citizens shows the degree to which they'll go to preserve their power. If anything, that's a reason to slowly bleed them instead of cornering and escalating.

The evil of your enemy does not excuse your own strategic stupidity or cruelty.

Arguably the country that has done the most to cement the Iranian regime is the United States with its sanctions. If Iran had been left to develop into a normal Middle Eastern oil-rich country then things might have turned out differently. The more money people have the harder it is to control them.